Browsing by Author "Rose Mary Francies"

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Characterisation of drought tolerance in rice (Oryza sativa L.) genotypes
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Jeevan, S; Rose Mary Francies
Characterisation of pumpkin (Cucurbita moschata duch.) varieties through morphological and molecular markers
(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Agina Gopan; Rose Mary Francies
Pumpkin (Cucurbita moschata Duch.), a crop of Central Mexican origin belonging to the family Cucurbitaceae, is popularly cultivated and valued in Kerala as a vegetable. The tender, large and often round immature fruits of pumpkin with a thick, smooth to slightly ribbed skin, which is mostly deep yellow to orange in colour, is an integral part of the Kerala cuisine. Despite its popularity in the state, few high yielding varieties are in cultivation. To ensure increased production, availability of high quality seeds of improved varieties or hybrids has to be guaranteed. Pumpkin being a cross pollinated crop, occurrence of cross contamination during its seed programme cannot be overruled. Hence, ensuring the purity and identity of seeds of the variety before sale becomes inevitable. Considering the importance of varietal identification in maintaining the genuineness and quality of seeds in seed production programmes, the present investigation envisaged to characterise six pumpkin varieties in the seed chain using morphological and molecular markers, and to generate fingerprints or molecular ID’s of the six varieties using selected polymorphic Inter-simple sequence repeats (ISSR) and Simple sequence repeats (SSR) markers. Characterisation of pumpkin varieties based on 28 quantitative and 16 qualitative traits was done using DUS and NBPGR descriptors. Qualitative vegetative traits like tendril characteristics (presence or absence of tendril, nature of coiling and branching) and leaf shape were not useful for grouping the varieties. Similarly, among the qualitative fruit characteristics, waxiness of mature fruit skin also proved insufficient to distinguish the varieties. Fruit shape was round flat in varieties Ambili, Suvarna and CO-2, while it was elongate/oblong in Saras, club shaped in CO-1 and flattish round in Arka Chandan. Based on qualitative traits, variety Arka Chandan could be clearly distinguished from the other varieties based on poor early growth vigour, moderately incised leaf blade margin, absence of silver patches on leaf blade, flattish round fruit shape, light green immature fruits and dark orange fruit flesh colour. In addition, the seeds of the Arka Chandan had a characteristic marking on the dorso-ventral surfaces unlike other varieties. Quantitative traits proved to be more useful than the qualitative traits for effective identification and categorisation of varieties. Results revealed that among the quantitative traits studied, leaf dimensions (blade length and width) and length of petiole could not be employed for distinguishing the six varieties. Variety Ambili flowered the earliest (49.25 days) and also possessed highly pubescent leaves, while variety Arka Chandan was late flowering (68.00 days). Peduncle length, fruit length and most of the seed dimensions (seed count per fruit, 100 seed weight, width and thickness of seed) was the least in this variety. In general, the size of seeds in varieties CO-1 and CO-2 was higher than those of others. Cluster analysis grouped Arka Chandan (Cluster V) and varieties CO-1 and CO-2 (Cluster IV) the farthest with an inter-cluster distance of 212.25. Principal component (PC) analysis indicated that trait components in PC1 registered an Eigen value of 16.79 and the traits in PC1 contributed 58 per cent to the variability among the varieties, emphasising their utility in identification of varieties. Among the 33 ISSR markers, 28 exhibited polymorphism. The total number of amplicons detected by an individual primer ranged from 4 in UBC-818 to 18 in UBC-847. High polymorphic information content (PIC) value was observed in UBC-809, whereas, low PIC was recorded in UBC-818. The six varieties grouped into four clusters based on ISSR binary data. Out of 20 SSR markers used for genotyping, only five showed polymorphism. The highest Jaccard’s similarity value (1.00) was observed between Saras and Suvarna. The most dissimilar varieties were Saras and Arka Chandan, and Suvarna and Arka Chandan, with a similarity coefficient of 0.12 each. The clustering algorithm grouped the varieties into four clusters. The polymorphic SSRs could be efficiently utilised for distinguishing Arka Chandan and therefore can prove useful for testing the genetic purity of this variety. Unique bands producing ISSR markers were used to generate variety specific DNA fingerprints. No single primer per se proved useful in distinguishing all six pumpkin varieties. However, ISSR primer UBC-822 could distinguish four out of six varieties studied. It produced unique amplicons of size 473 bp, 552 bp, 1403 bp and 517 bp, respectively in Ambili, Saras, CO-1 and Arka Chandan, proving its utility in testing for genuiness and purity of seed lot. In general, it can be concluded that the correlation that existed between morphological and molecular assessments was of medium magnitude. The absence of high consensus between the assessments should not be considered a limitation of these tools to characterize and quantify variability. It only indicates that both morphological and molecular characterisation is important and play a complementary role in providing a better understanding and differentiation of the pumpkin varieties.
Combining ability for tolerance to iron toxicity in rice (Oryza sativa L.)
(Department of plant breeding and genetics, College of horticulture, Vellanikkara, 2015) Tess Joseph; Rose Mary Francies
Effect of seed protectants against pulse beetle on viability, vigour and health of cowpea seeds
(Department of Seed Science and Technology,College of Horticulture, Vellanikkara, 2016) Libi Antony, A; Rose Mary Francies
Experiments to assess the effectiveness of seed protectants against cowpea pulse beetle (Callosobruchus spp.)and their impact on seed quality and seedling vigour of selected cowpea varieties were conducted at College of Horticulture, Vellanikkara during 2014-2016. Separate experiments were conducted for both Lola and Kanakamony varieties following a completely randomized design with 13 treatments and three replications. Seeds were treated with seed protectants viz. neem oil, castor oil, coconut oil, sweet flag rhizome powder, neem leaf powder, paanal leaf powder, karinotchi leaf powder, neem kernel powder, diatomaceous earth, rice husk ash, Beauveria bassiana and spinosad. Untreated seeds served as control. Both treated and untreated seeds were dried to nine per cent moisture content were stored under ambient conditions for a period of 13 months. The seed quality parameters like germination, speed of germination, seedling vigour indices, electrical conductivity of seed leachate, mortality of adult pulse beetles, number of eggs laid by beetle, egg hatchability and seed infestation were recorded at monthly intervals. Seed microflora infection per cent were recorded at start and end of storage period.The results revealed that germination and other seed quality parameters in both treated and untreated seeds decreased progressively over the storage period.However, irrespective of the variety, the seed protectants significantly enhanced the viability and quality of treated seeds. The quality of treated seeds was higher than that of untreated seeds for most part of the storage period. The germination in untreated seeds was retained above 75 per cent (the minimum seed certification standards (MSCS) required for cowpea) for eight months while it was retained for nine months in all treated seeds. The rate of decrease in seed germination and quality was slower in semitrailing variety Kanakamony compared to trailing variety Lola. In both the varieties, the germination was lower in untreated seeds in comparison to the treated seeds. Germination, speed of germination, seedling growth parameters and vigour indices were invariably high in seeds treated with neem based seed protectants viz., neem kernel powder, neem leaf powder and neem oil. Among the neem based botanicals used, seed treatment with neem kernel powder maintained higher germination and seed quality parameters viz., seedling shoot length, seedling root length, seedling dry weight and seedling vigour index I and II during storage. Similarly, the electrical conductivity of seed leachate and per cent infection by seed microflora was found to be consistently low in seeds treated with neem based botanicals, vegetable oils and spinosad.The efficacy of seed protectants against pulse beetle was evaluated at monthly intervals by recording weight of infested seed, seed infestation, mortality, fecundity and egg hatchability in twenty five seeds drawn randomly from each replication. The results revealed that all the seed protectants used were effective against pulse beetle during the initial period of storage and were significantly superior to control over the period of storage.Among the seed protectants evaluated, highest mortality of adult beetles,lowest fecundity, egg hatchability and seed infestation were recorded in seeds treated with spinosad followed by oils viz., neem oil, coconut oil and castor oil as well as other neem based botanicals. Seed treated with spinosad offered protection against pulse beetle for up to seven months of storage as evident from the cent per cent mortality of adult beetles, complete suppression of egg hatchability as well as low seed infestation in both varieties. Seeds treated with neem oil, castor oil, coconut oil, neem kernel powder and neem leaf powder recorded cent per cent mortality of adult beetles for five months of storage in both varieties. No seed infestation was recorded in seeds treated with neem oil, castor oil and coconut oil for up to five months of storage while a similar protection was offered by neem leaf powder and neem kernel powder for up to four months of storage. Spinosad was found to be the most effective in controlling pulse beetle infestation throughout the storage period. Based on the impact of seed protectants on seed viability, seedling performance as well as protection against pulse beetle infestation in cowpea, seed treatment with seed protectants viz., spinosad or neem based products (neem kernel powder, neem leaf powder and neem oil) or as oils (coconut oil and castor oil) can be recommended to be most effective in enhancing seed viability (by a period of one month over control), higher seed and seedling performance and protection from pulse beetle infestation and infection by microflora in cowpea. Among the above Spinosad can be recommended as the best seed treatment for cowpea if it can ensured that the treated seeds would be used only for seed purpose. However, in case the stored pulse seeds are meant for use as food, feed and seed, treatment with coconut oil could be recommended in place of neem based products since neem based botanicals are reported to cause sterility in humans and animals.
Formation of core set in rice (Oryza sativa L.) short duration germplasm accessions
(Department of plant breeding and genetics, College of horticulture, Vellanikkara, 2012) Pawan Saini; Rose Mary Francies
Gene pyramiding for bacterial blight resistance in rice variety Uma (Mo 16)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2016) Tintumol Joseph; Rose Mary Francies
Exploiting host-plant resistance through pyramiding of resistance genes have been recommended as the best approach to impart durable resistance to rice varieties in order to combat the bacterial blight (BB) disease caused by Xanthomonas oryzae pv.oryzae (Xoo). In lieu of this, F1s were produced by hybridizing the susceptible elite rice variety Uma with resistant donor parent Improved Samba Mahsuri (ISM) harbouring three R-genes xa5, xa13 and Xa21. BC1F1 individuals were generated by backcrossing the F1s using variety Uma as the recurrent parent. The present study aimed to identify the R-genes introgressed individuals in the BC1F1 population as well as to produce BC2F1s and BC1F2s of the identified R-genes introgressed BC1F1s. Foreground selection of the BC1F1 individuals was done using the R gene linked molecular markers. Restriction digestion of the PCR product of STS marker RG 556, linked to R gene xa5, with Dra1 restriction enzyme, resulted in production of alleles of size 128 bp, 514 bp, 587 bp, 624 bp, 650 bp and 836 bp in all the BC1F1 individuals as well as the parents indicating the presence of R gene xa5 in all the individuals studied. Amplification of DNA of the individuals with the functional marker xa5 SR further confirmed the presence of R gene xa5 in both the parents as well as in all the BC1F1s. Restriction digestion of the PCR product of STS marker RG 136, linked to R gene xa13, with Hinf1, produced alleles similar to that of the donor parent ISM in three BC1F1s namely, plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9, indicating the presence of R gene xa13 in these plants. The presence of gene xa13 in the identified BC1F1s was further affirmed by using the functional marker xa13 promoter. The analysis had resulted in the production of 560bp allele associated with the resistant allele of gene xa13 in homozygous state from donor parent ISM in the three BC1F1s mentioned above. Out of the 95 BC1F1 individuals scored with the STS marker pTA 248 linked to R gene Xa21, only BC1F1s plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 were found to possess Xa 21. Results thus obtained revealed thatBC1F1plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 were R gene pyramids (xa 5+xa 13+ Xa 21). Background profiling of the three R-genes introgressed BC1F1s using 22 rice microsatellite markers, revealed presence of the donor parent allele in the homozygous state. PCR analysis with the marker RM 307, however, revealed the presence of alleles from both the parents, ISM and Uma in the BC1F1 plant no. 8.3.2. This indicated that the plant was heterozygous at the marker locus and can be expected to segregate for the alleles at this locus in subsequent generations. Considering the segregation of the 22 markers the per cent recurrent parent genome recovery in the R-genes introgressed BC1F1s was estimated to be higher in BC1F1 plant no.8.3.2 but lower than the expected estimate of 75 per cent. This was also confirmed by graphical genotyping. The dendrogram thus generated out of the marker data, grouped the R-genes introgressed BC1F1s with ISM indicating that the three R-genes introgressed BC1F1s exhibited greater similarity with donor parent parent ISM at the genome level. Evaluation of BC1F1 individuals for morphological traits revealed presence of wide variability. The three R-genes introgressed BC1F1s were late in flowering compared to the recurrent parent Uma. Two of these genotypes i.e.,plant no. 8.3.2 (234 days) and plant no. 8.3.3 (228 days) flowered later than the donor parent. However, the three R-genes introgressed BC1F1s resembled the recurrent parent Uma with respect to grain and kernel characteristics. Backcrossing the three R-genes introgressed BC1F1s i.e., plant no. 8.3.2, plant no. 8.3.3 and plant no. 8.3.9 to the recurrent parent Uma resulted in 28 BC2F1s. Simultaneously, selfing of these individuals produced 850 BC1F2 seeds. Foreground and background profiling of these generations can ensure precise identification of genotypes that resembles the recurrent parent Uma possessing the resistance genes of interest with maximum recovery of recurrent parent genome.
Genetic analysis of certain clones,hybrids and inbreds in cocoa
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1998) Rose Mary Francies; Achamma Oommen
Genetic studies in cocoa (Theobroma cacao L.) using various population viz., clones, biclonal crosses, biclonal pair crosses and inbreds were undertaken in College of Horticulture, Kerala Agricultural University, Thrissur, during 1994-97. The study assessed variability, association of yield attributes and relative importance of these attributes for yield variation using multiple regression and path analysis. Selection indices, inbreeding depression and limits to genetic diversity for heterosis were also worked out. Wide spectrum of variability existed in the populations studied. The highest variability was observed in yield of dry beans/tree and precocity of bearing (pods/tree - 5 years from planting), whereas, traits pod width and bean width showed low variability. Clones GI 10.2, S 27.16, GI 14.17 of Clonal base population, hybrids H'8 (GI 5.9 x GII 23.3), H2 (M 13.12 x GI 5.9) of Series IV biclonal crosses and hybrids H4 (M 16.9 x GII 19:5), H3 (M 16.9 x GII 20.4) of Series 11 biclonal crosses, exhibited superior yield - performance. Yield however, recorded only moderate heritability and therefore moderate expected genetic advance. Strong correlation was observed for yield with pod weight, dry weight/bean and efficiency index but not with precocity of bearing, chlorophyll contents and net photosynthesis rate. Multiple regression and path analysis revealed the importance of dry weight/bean, bean size and efficiency index in determining the yield in cocoa. High correlation exhibited by many traits was due to indirect effects. Selection index for yield, based on the above traits viz., dry weight/bean, bean length, bean thickness and efficiency index recorded a relative efficiency of 150.35 per cent over direct selection. Inbreeding depression was observed for growth traits. The rate of depression was more in the second inbred generation as compared to that in the first inbred generation. Number of hybrids exhibiting relative heterosis in desirable direction ranged from one (eg. pod width, bean length and thickness) to seventeen (number of beans/pod). Considerable genetic divergence among clonal genotypes was evident. Results indicated that the chances for occurrence of a high frequency of heterotic crosses and high values of heterosis are more, when the parental divergence is moderate.
Halogenation of rice seeds to prolong storability
(Department of seed science and technology, College of horticulture,Vellanikkara, 2015) Suganya, S; Rose Mary Francies
An experiment on the effect of halogens and packing materials on paddy seeds was undertaken at the Department of Seed Science and Technology, College of Horticulture, Kerala Agricultural University (KAU), Vellanikkara, Thrissur with seeds of rice variety Jyothi pertaining to rabi 2013-14, summer 2013-14 and kharif 2014. The experiment aimed to standardize the optimum dose and mode of application of halogens and elucidate the impact of seed treatment with halogen and the packing material on seed quality and longevity. The experiment was conducted as completely randomized design involving two factors (packing material and halogenation dose) with two replications. Treatments comprised of a combination of a packing material either jute bag (P1) or polyethylene bag of 400G (P2) with seed halogenation (T) at different doses. Observations recorded on germination, seedling shoot and root length, seedling dry weight, seedling vigour index I and II, electrical conductivity of seed leachate, seed moisture content and seed infection were statistically analyzed and results interpreted. Seed quality and longevity during storage were found to be significantly influenced by packing material, dose of halogen and the interaction effects of packing material and dose of halogen throughout the storage period. Irrespective of halogenation, seeds of all the three seasons stored in polyethylene bags (400G) were significantly superior to that in jute bags with respect to germination and other seed quality parameters like seedling length, seedling dry weight, seedling vigour index I and II, electrical conductivity of seed leachate, seed moisture content and infection by seed microflora at the end of storage. Seeds of rabi and summer 2013-14 stored in polyethylene bags (400G) retained viability above minimum seed certification standards (MSCS) (80%) for eleven and eight months compared to eight and four months in case of jute bags respectively. Hence, results pointed out that there was definite advantage in storing seeds in polyethylene bags (400G) over storing them in jute bags both with respect to seed qualities and prolonging seed longevity. Seeds halogenated with calcium oxychloride (CaOCl2) in combination with carrier calcium carbonate (CaCO3) @ 3g each/kg of seed (T5) recorded significantly high germination, seedling shoot length, seedling dry weight and seedling vigour index I and II. It also recorded the least electrical conductivity, moisture content and seed infection at the end of storage irrespective of the packing material and season of seed production. In addition, T5 prolonged seed viability above MSCS for a period of twelve and nine months compared to nine and six months in untreated seeds (T1) in rabi and summer 2013-14 respectively. Results thus proved the superiority of halogenation at T5 (CaOCl2+CaCO3@ 3g each/kg seed) in retaining seed qualities and prolonging seed longevity during storage. T3 (CaOCl2 @ 6 g/kg seed) that exhibited lower seed deterioration next to T5 retained viability above 80 per cent for nine and seven months in rabi and summer 2013-14 respectively, is adjudged the next best halogenation dose. The interactive effect of packing material and seed halogenation indicated that, seed treated with CaOCl2 through carrier CaCO3 @ 3g each /kg of seed (T5) and stored in polyethylene bags of 400G (P2) i.e., treatment combination P2T5, exhibited significantly higher seed qualities at the end of storage in all three seasons. P2T5 had also retained viability above MSCS for longer period both in rabi and summer 2013-14 (fourteen and ten months respectively) compared to untreated seeds packed in jute bag (P1T1) (eight months and six months respectively). Among the various combinations, P1T5 (CaOCl2+CaCO3 @ 3g each/kg seed and packing in jute bag) was found consistent in all three seasons with respect to maintain seed quality parameters at the end of storage. Seeds in P1T5 had retained viability above MSCS for eleven and eight months in rabi and summer 2013-14 respectively, indicating its advantage over untreated seeds packed in jute bag (P1T1). Hence, halogenation with calcium oxychloride through carrier calcium carbonate (T5) and packing in jute bags is also a viable option for prolonging seed longevity. Considering the above, it can be concluded that, to maintain higher seed quality and prolonging viability during storage, it is best advisable to store rice seeds in moisture vapour proof polyethylene bags (400G) at ten per cent moisture after treating with halogen calcium oxychloride along with carrier calcium carbonate @ 3g each/ kg of seed i.e., P2T5 followed by P1T5 (CaOCl2+CaCO3 @ 3g each/kg seed and packing in jute bag).
Identification of molecular markers linked to iron toxicity tolerance through bulk segregant analysis (BSA) in rice (Oryza sativa L.)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2016) Amaranatha Reddy, M; Rose Mary Francies
Globally rice is the most important food crop, serving as staple food for more than half of the world’s population. As in other parts of the country, rice is the major food crop grown in Kerala too. The total annual production of rice is however insufficient to meet the total demand in the state. Iron toxicity prevalent in the rice growing tracts of the state, further compounds the problem of low rice production. Although, several attempts to ameliorate the iron toxic soil conditions are being made, the best way to combat this stress and increase rice production in the affected soils is to develop varieties tolerant to iron toxicity. The present investigation on 'Identification of molecular markers linked to iron toxicity tolerance through bulk segregant analysis (BSA) in rice (Oryza sativa L.)’ was conducted at College of Horticulture, Kerala Agricultural University (KAU), Vellanikkara, Thrissur during 2013 to 2015 year. The study involved screening of thirty rice genotypes for response to iron at toxic levels, hybridization between the most tolerant and susceptible genotype, production of F2 generation of this cross, parental polymorphism study using molecular markers and Bulk Segregant Analysis (BSA). The thirty rice genotypes were selected on the basis of their response to iron stress under KSCSTE project: ‘Donor identification for tolerance to iron toxicity in rice (Oryza sativa L.)’. Further screening of the thirty genotypes (Confirmation test 1 and 2) as per the method advocated by Shimizu et al. (2005) to confirm their tolerance or susceptibility to iron toxicity revealed existence of high significant differences among the genotypes with respect to leaf bronzing and biomass produced under varying concentrations of iron (0 ppm, 600ppm and 800ppm of Fe). Considering that at higher concentrations of Fe, a lower leaf bronzing and reduction in biomass, is a valid criterion for identifying genotypes tolerant to Fe stress, twelve genotypes viz., Cul-8709, Cul-210-29, AM-10-7, Cul-90-03, PM-709, ASD-16, ASD-18, Abhaya, IR-1552, T(N)-1, IR-36 and Cul-3 213 were found to be highly susceptible to iron stress while genotypes Cul-8723, Tulasi, Cul-18716, Kargi and IVT-33 were identified as the most tolerant ones. Selfing of F1s obtained on hybridizing the genotype (Tulasi) and genotype (CUL-8709) which were found respectively to be most tolerant and most susceptible to iron stress was done, to produce F2 population for the conduct of bulk sergegant analysis (BSA). Phenotyping of F2 plants under iron at toxic levels indicated presence of wide variability for shoot length, root length, total number of roots, number of fresh roots, shoot weight, root weight and visual scoring for iron-toxicity symptoms. The measures of skewness and kurtosis for various traits revealed a large quantitative variability. All the above traits except iron content in root of F2 lines exhibited a positive platykurtic distribution pointing to presence of gene interaction in trait expression. Measures of skewness and kurtosis also indicated occurrence of transgressive segregation in the F2 population. Leaf bronzing the typical symptom of Fe toxicity, showed a strong negative correlation with shoot length, root length, total number of roots, number of fresh roots, shoot weight and root weight. The results indicated that leaf bronzing is associated with growth reduction due to Fe2+ toxicity in this F2 population. Parental polymorphism (Tulasi and CUL-8709) survey using 338 Rice Microsatellites (RM) markers revealed 37 RM markers polymorphic between the two. These 37 polymorphic rice microsatellites markers (SSR markers) were found to be distributed over all 12 linkage groups of rice varying between one in case on Chromosome 7 to five each on Chromosome 2, 9 and 10. Bulk segregant analysis indicated that out of the 37 microsatellite markers that were polymorphic between parents seven viz., RM 263, RM 107, RM 12292, RM 24616, RM 24664, RM 13619 showed clear co-segregation with the susceptible parent and susceptible bulk, and resistant parent and resistant bulk. Probability of all seven putative markers was highly significant (P < 0.001) indicating strong association of these markers to the genomic region governing Leaf Bronzing Index which is a valid indicator of tolerance to iron toxicity. Through single marker analysis, three probable quantitative trait loci (QTL’s) of Leaf Bronzing Index were identified, each on 214 chromosome 1, 2 and 9. The QTL on chromosome 1 was located between 42.8 Mb and 43.2 Mb and associated with markers RM 12255 and RM 12292. The QTL for LBI was found to be associated with RM 13619 and RM 263 markers and placed between 24.9 Mb and 25.9 Mb on chromosome 2 while on chromosome 9, it was a located between 19.3 Mb and 20.1 Mb and linked to marker RM 107, RM 24616 and RM 24664.
Impact of foliar application of nutrients and growth promoters on seed yield and quality of okra
(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2018) Nishidha, C T; Rose Mary Francies
Impact of pre-storage seed invigoration in ash gourd (benincasa hispida (thunb.) cogn.)
(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2018) Athmaja, S; Rose Mary Francies
A study to elucidate the effect of seed invigoration on viability and quality of seeds in ash gourd variety KAU Local was conducted at College of Horticulture, Vellanikkara, Thrissur, during 2016-2018. The impact of seed invigoration on seed viability and seed quality parameters under ambient (S1) and refrigerated storage (S2) was assessed following a completely randomized design with seven invigoration treatments (I1 to I7) and three replications. Seeds were separately invigorated using CaCl2 (50 m M) for 12h (I1), CaCl2 (50 mM) for 24h (I2), kinetin (10 ppm) for 12h (I3), kinetin (10 ppm) for 24h (I4), KH2PO4 (10-1 M) for 24h (I5), Pseudomonas fluorescens (1x106 cfu.ml-1) for 12h (I6). Untreated seeds (I7) served as control. Both treated and untreated seeds were dried to < 8 per cent moisture content and packed in polythene bags (700 gauge). The seed quality parameters were recorded immediately after treatment and subsequently at monthly intervals for a period of 10 months, while, germination of stored seeds was assessed up to 14 months after storage (MAS). At bimonthly intervals, quantification of lipid peroxidation, sugar and amino acids leached out from the seeds and the seed micro flora infection was also done. Seed quality during storage and seed longevity were found to be significantly influenced by storage environment, invigoration treatment and their interaction throughout the storage period. The results revealed that germination and other seed quality parameters such as germination index, coefficient of velocity of germination, energy of germination, vigour indices I and II, in both treated and untreated seeds decreased progressively over the storage period. However, there was an increase in mean time to germination, time taken for 50 per cent germination, allometric index, electrical conductivity of seed leachate, seed infection per cent, leachate of sugar, amino acid and lipid peroxidation, towards the end of storage period. Germination of seeds stored under the refrigerated storage was lower than that under ambient storage in the initial storage period (upto 3 MAS). Henceforth, refrigerated seeds exhibited significant superior germination than that under ambient storage till the end of storage period (14 MAS). Germination of seeds under refrigeration was retained above 60 per cent (the minimum seed certification standards required for ash gourd) for 13 MAS compared to 5 MAS in ambient stored seeds. The study thus revealed that irrespective of seed invigoration treatments, to prolong seed longevity and maintain seed quality, storing seeds under refrigeration is advantageous over ambient storage. Irrespective of storage environment, priming induced early germination. The seed quality parameters of the invigorated seeds before storage were found to be superior to untreated seeds. The invigorated seeds had also exhibited a germination per cent above 80 at 1 MAS, while, the germination in untreated control (I7) during the corresponding period was below the MSCS. Seeds invigoration with calcium chloride for 12h (I1) and 24h (I2) recorded significantly high germination and other seed quality parameters during the storage period of ten months. Owing to the significant superiority of seeds invigorated with I1 (CaCl2 50mM 12h) and I2 (CaCl2 50mM 24h) with respect to germination in the initial period of storage (up to 4 MAS), superior seed qualities during storage as well as retention of germination above MSCS for 8 MAS, seed invigoration with CaCl2 50mM before storage can be advocated to help retain seed qualities and prolonging seed longevity during storage. The interaction between storage condition and invigoration treatment on germination and other seed indices pointed out that it was most advantageous to treat seeds with CaCl2 50mM for 12h (I1) before storing under ambient conditions. If provision for refrigerated storage is available, bio-priming with Pf 1x10-6 cfu.ml-1 for 12h (S2I6) or priming with CaCl2 50mM for 24h (I2), kinetin 10 ppm for 12h (I3) or kinetin 10 ppm for 24h (I4) or KH2PO4 10-1 M for 24h (I5) would be most advantageous. Analysis of the impact of pre-storage seed invigoration treatment on seed longevity subsequent to retrieval of seeds from refrigerated storage revealed that, irrespective of the storage period under refrigeration, the seeds were found to retain viability above MSCS for a minimum period of one month after retrieval from refrigerated storage. Viability retention of invigorated and untreated seeds during further periods of thawing was unpredictable. It was also evident that none of the treatments could help retain seed viability above MSCS for five months after retrieval from refrigeration. Results also revealed that seed invigoration with CaCl2 50mM 12h (I1) is advantageous, if one or two months of ambient storage after retrieval from cold storage is unavoidable. Hence, considering the impact of storage environment, invigoration treatment and their interaction on seed longevity and quality, as well as their influence on seed longevity during thawing, it can be summarised that seed invigoration with CaCl2 50mM for 12h (I1) or 24h (I2) would be beneficial.
Impact of seed protectants on seed longevity and storage pests in rice (Oryza sativa L.)
(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2020) Hariprasad, K; Rose Mary Francies
Influence of storage structure on seed longevity in rice (Oryza sativa L.)
(Department Seed Science and Technology, College of Horticulture, Vellanikkara, 2020) Jyothish Babu, E; Rose Mary Francies
Marker assisted backcross breeding for pyramiding genes conferring resistance to bacterial blight in rice variety uma
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2018) Megha, L M; Rose Mary Francies
As in other rice growing locales around the world, bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) assumes a huge role in deciding rice profitability in Kerala. The elite rice varieties of Kerala, both PTB 39 (Jyothi) and Mo 16 (Uma), are found to be extremely susceptible to bacterial blight. Since both the major rice cropping seasons (virippu and mundakan) in the state coincide with monsoons, the control of the disease through chemicals or biological agents proves inadequate owing to the washing-off of the applied materials. Host-plant resistance is advocated as the most effective breeding strategy to combat the bacterial blight (BB) pathogen. Considering the impact of the disease on food security and sustainability, efforts were taken to introgress three R-genes (xa5, xa13 and Xa21) into the variety Uma from donor parent Improved Samba Mahsuri (ISM) through Marker Assisted Selection (MAS). Further, backcrossing to Uma (recurrent parent) and advancing the resultant BC1F1s have resulted in production of BC2F1 generation (21 Nos.). The present study aimed to identify BC2F1 plants pyramided with genes (xa5, xa13 and Xa21) conferring resistance to bacterial blight using functional markers. In addition, advancing the R-gene introgressed BC2F1s to BC3F1 and BC2F2 generation was envisaged. Pathotyping of BC1F2s (850 Nos.) and generating BC1F3s from the plants exhibiting resistance to BB pathogen was also aimed at. Foreground selection of the BC2F1 individuals using the xa5 gene linked STS marker RG 556 and functional marker xa5 SR confirmed the presence of the R-gene in the parents as well as the 21 BC2F1 individuals. Screening of BC2F1 individuals with STS marker RG 136 linked to R-gene xa13 and functional marker xa13 promoter revealed that the BC2F1 Plant No. 8.3.9.10 was heterozygous at xa13 locus while, all other BC2F1 individuals possessed alleles similar to that of the recurrent parent (RP) Uma. The result also pointed out that BC2F1 Plant No. 8.3.9.10 was a 2-R-gene pyramid (xa5xa5 + Xa13xa13). Foreground selection with STS marker pTA 248 to detect the presence of Xa21 gene revealed that none of the BC2F1 plants analysed except BC2F1 Plant No. 8.3.9.10, possessed the resistant allele of R-gene Xa21. However, presence of alleles of both the parents in Plant No. 8.3.9.10 indicated that it was heterozygous at Xa21 locus. Results obtained thus revealed that, of the 21 BC2F1s subjected to foreground selection, BC2F1 Plant No. 8.3.9.10 was the only 3-R-gene introgressed pyramid (xa5xa5 + Xa13xa13 + Xa21xa21). In addition, the 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was subjected to background screening using 22 rice microsatellite (RM) markers. Background profiling revealed that the banding pattern in Plant No. 8.3.9.10 was similar to recurrent parent in case of thirteen RM markers. The plant was found to be heterozygous at five other marker loci. Considering the segregation of the 22 markers, the magnitude of recovery of recurrent parent genome in 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was found to be 81.82 per cent. The dendrogram based on molecular data grouped the individuals into two major clusters. Cluster 1 was monogenic with only the donor parent ISM and cluster 2 comprised of the recurrent parent Uma and Plant No.8.3.9.10, further suggesting that the 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was more similar to the recurrent parent Uma. Wide variability was observed among the BC2F1 individuals for various morphological traits. The 3-R-gene introgressed BC2F1 Plant No. 8.3.9.10 was shorter in duration than both the parents and also possessed red kernels similar to the recurrent parent Uma. The dendrogram generated based on the morphological characters also indicated greater similarity between the 3-R-gene pyramid and recurrent parent Uma. The identified 3-R-gene pyramid (BC2F1 Plant No. 8.3.9.10) was backcrossed to both recurrent parent Uma as well as selfed resulting in production of BC3F1s (15 Nos.) and BC2F2s (28 Nos.) respectively. Bioassay of BC1F2 population (106 Nos.) through leaf clipping method of pathotyping suggested by IRRI (1991) revealed that more than half the BC1F2 individuals screened exhibited resistance to BB pathogen. The plants that exhibited moderate reaction to BB infection ranged between 16.87 per cent and 34.78 per cent in progeny of BC1F2 Plant No. 8.3.2 and BC1F2 Plant No. 8.3.9 respectively. Selfing of the BC1F2 individuals exhibiting resistance and moderate resistance to BB pathogen resulted in production of 725 BC1F3 seeds. Modern molecular techniques make it possible to use markers and probes to track the simultaneous introgression of several R-genes into a single cultivar during a crossing programme. Foreground and background profiling of backcross generations can ensure precise identification of R-gene introgressed genotypes that resemble the recurrent parent Uma.
Marker assisted backross breeding in two-R gene pyramid lines of rice variety Jyothi for bacterial blight resistence
(Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara, 2019) Nayana Nayak; Rose Mary Francies
Rice variety Ptb 39, also known as Jyothi, is extremely popular amongst farmers and consumers of Kerala. Despite its popularity, the variety is highly susceptible to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo). The climatic conditions prevailing in the state enhances the occurrence and spread of the bacterial blight disease. In both rice growing seasons (Kharif and rabi), spraying of antibiotics is not much effective, as it is often washed-off during the monsoon showers. Moreover, both the researchers and the consumers are concerned about the food safety aspects as well as the negative impact of plant protection chemicals on the environment. Hence, the best alternative is to exploit host-plant resistance by pyramiding multiple R-genes to impart durable and broad- spectrum stable resistance to varieties against the pathogen. Considering the impact of the BB disease on food security and sustainability, efforts to introgress the three R-genes (xa5, xa13 and Xa21) into the elite cultivar Jyothi (Ptb 39) through Marker Assisted Selection (MAS) were initiated at College of Horticulture, Vellanikkara. Improved Samba Mahsuri (ISM) was used as the donor parent. The present study aimed to identify R-gene pyramided plants in BC1F₁ population and to develop stable pyramided BC2F1 lines of variety Jyothi with low linkage drag from the donor parent (ISM). It also aimed to evaluate the BC2F5 population for resistance to BB pathogen (pathotyping) and production of next-generation backcross populations (BC2F1s, BC1F2s and BC2F6). The good quality DNA, isolated from BC1F1s (24 Nos.) and parents (ISM and Jyothi) was subjected to foreground selection to identify the plants introgressed with the three R-genes, using markers RG556 and xa5 SR, RG136 and xa13 promoter, and pTA248 linked to xa5, xa13 and Xa21, respectively. Monomorphic banding pattern was observed in all the BC1F1s as well as the parents on analysis with markers RG556 and xa5 SR, pointing to the endogenous presence of R-gene xa5 in all the individuals tested. Screening of BC1F1 individuals with STS marker RG 136 linked to R-gene xa13 and functional marker xa13 promoter revealed that the three BC1F1s i.e., Plant No. 9.7, Plant No. 9.15 and Plant No. 9.17 were heterozygous at xa13 locus while, all other BC1F1 individuals possessed alleles similar to that of the recurrent parent (RP) Jyothi. The result thus pointed out that BC1F1 Plant No. 9.7, Plant No. 9.15 and Plant No. 9.17 were 2-R-gene pyramids (xa5xa5 + Xa13xa13). Foreground selection with STS marker pTA 248 to detect the presence of Xa21 gene revealed that the above mentioned three BC1F1s were heterozygous at Xa21 locus. Results of foreground selection, thus indicated that three BC1F1 plants, i.e., Plant No. 9.7, Plant No. 9.15 and Plant No. 9.17 were the only 3-R-gene pyramids (xa5xa5 + Xa13xa13 + Xa21xa21) among the 24 BC1F1 individuals investigated. The other BC1F1s possessed only a single recessive R- gene xa5. Background selection of the three BC1F1 3-R gene pyramids was done using 58 microsatellite markers. The profiles revealed that BC1F1 Plant No. 9.7, Plant No. 9.15 and Plant No. 9.17 were similar to recurrent parent Jyothi and donor parent ISM at 24 and 21 marker loci, 22 and 21 marker loci, and 34 and 12 marker loci, respectively and heterozygous at 13, 15 and 12 marker loci respectively. Dendrogram based on molecular data, further suggested that the 3-R-gene introgressed BC1F1s were more similar to the recurrent parent Jyothi than to the donor parent ISM. The recovery of the recurrent patent genome was found to be the highest in Plant No. 9.17 (93.00 %) while, it was 89.00 per cent each in Plant No. 9.7 and Plant No. 9.15. Morphological characterisation revealed that the 3-R-gene introgressed BC1F1s Plant No. 9.7 and Plant No. 9.15 and Plant No. 9.17 exhibited about 60 per cent similarity to the parents Jyothi and ISM. BC1F1 Plant No.9.17 was near similar to the recurrent parent Jyothi with respect to the days to flowering, plant height, seed length and width as well as kernel colour. However, the length of panicles and the number of spikelets per panicle in the selected BC1F1s were found to be less than that of the parents. The identified 3-R-gene pyramids (BC1F1 Plant No. 9.7; 9.15 and 9.17) were backcrossed to recurrent parent Jyothi as well as selfed resulting in production of BC2F1s (5 Nos.) and BC1F2s (220 Nos.). Wide variability was observed among the BC2F5 individuals (111 Nos.) for various morphological traits. Pathotyping of BC2F5 population through leaf clipping method, as suggested by IRRI (2002), revealed that 11.71 per cent (13 Nos.) of the progenies exhibited resistance reaction to BB infection, while, 10 (9.00 %) were moderately resistant, 24 (21.62 %) moderately susceptible, 21 (18.91%) susceptible and 43 (38.73 %) highly susceptible. Selfing of the BC2F5 individuals exhibiting resistance and moderate resistance to BB pathogen resulted in production of 1425 BC2F6 seeds.
Marker assited pyramiding of bacterial blight resistance genes in backcross population of rice variety jyothi
(Department of Plant Biotechnology, College of Agriculture , Vellanikkara, 2023-04-03) Athira Rajan , P V; Rose Mary Francies
Rice variety Jyothi (PTB 39) is one among the most preferred and widely cultivated variety across Kerala. Despite its widespread popularity, the cultivar is highly susceptible to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo). Considering its efficiency, economic viability and eco-friendliness, host-plant resistance has been advocated as the best option to combat the BB pathogen. Advancements in the field of molecular biology such as marker-assisted selection (MAS) have paved ways for pyramiding multiple R-genes into a single genotype. In this context, efforts to introgress three R-genes (xa5, xa13 and Xa21) imparting resistance to BB into the rice variety PTB 39 (Jyothi; recurrent parent) from Improved Samba Mahsuri (ISM; donor parent) through marker assisted selection, was initiated at the College of Agriculture, Vellanikkara. The present study was formulated to identify BC2F1s and BC1F2s pyramided with the R- genes conferring resistance to bacterial blight (xa5, xa13 and Xa21), using functional marker as well as R-gene linked Sequence tagged site (STS) markers. Morphological characterisation of the population was also envisaged. Foreground selection in five BC2F1s along with the parents was done using good quality DNA isolated in order to identify plants introgressed with the three targeted R-genes. Markers RG556 and xa5SR/R linked to xa5, RG136 and xa13 prom linked to xa13 and pTA248 linked to Xa21 were used. Foreground profiling with RG556 and xa5SR/R resulted in monomorphic banding pattern in the experimental population revealing the endogenous presence of R-gene xa5. Screening of BC2F1s using RG136 and xa13-prom and pTA248 revealed the presence of amplicons similar to that found in the recurrent parent Jyothi in the backcross individuals, implying the absence of R-genes xa13 and Xa21 in BC2F1s. The results thus pointed out that the BC2F1s possessed only one R-gene i.e., xa5. Morphological characterisation of BC2F1s indicated that population exhibited similarity towards the recurrent parent Jyothi. Foreground profiling of BC1F2 (132 Nos.) and parents with markers RG556 and xa5SR/R linked to R-gene xa5 resulted in monomorphic banding pattern across the experimental population. This indicated the endogenous presence of the R-gene xa5 in BC1F2s as well as the parents. Presence of R-gene xa13 was evident in 35 BC1F2s i.e., five progenies of BC1F1 Plant No. 9.7, twenty-four progenies of BC1F1 Plant No. 9.15 and six progenies of BC1F1 Plant No. 9.17, on screening with R-gene xa13 linked markers RG136 and xa13-prom. Twenty-five R-gene pyramids, out of the 35, were deduced to be heterozygous at xa13 R-gene locus (xa5xa5+xa13Xa13), while 10 were found to be homozygous (xa5xa5+xa13xa13). Foreground selection for the R-gene Xa21 using pTA248 helped identify 31 BC1F2s introgressed with R-gene Xa21. Among them, 18 were found to be heterozygous (xa5xa5+Xa21xa21) and 13 were homozygous (xa5xa5+ Xa21Xa21), at the R-gene locus (Xa21). The foreground selection thus helped delineate 42 R-gene pyramids among the 132 BC1F2 individuals. Among them, twenty-four were identified to be 3-R-gene pyramids. This included four individuals (Plant No. 9.15.15, Plant No. 9.15.20, Plant No. 9.15.39 and Plant No. 9.17.8) homozygous at all three R-gene loci (xa5xa5+xa13xa13+Xa21Xa21). Background selection of the 24 three-R-gene pyramids identified was done using 52 SSR markers found to be polymorphic between the donor parent ISM and recurrent parent Jyothi. Results revealed the presence of wide variability among the backcross individuals with respect to segregation of marker loci as well as genome recovery from recurrent parent (RPGR). The maximum recovery of 61.90 per cent was found in Plant No. 9.15.59 followed by 59.40 per cent in Plant No. 9.17.8. The least recovery was observed in Plant No. 9.15.42 (27.90 %). The RPGR per cent for the four 3-R-gene pyramids homozygous at all three loci were 41.50 (Plant No. 9.15.15), 47.30 (Plant No. 9.15.20), 48.60 (Plant No. 9.15.39) and 49.40 (Plant No. 9.17.8). In general, the BC2F1s exhibited more similarity to the recurrent parent Jyothi rather than the donor parent for yield attributes and yield. However, none of the BC2F1s and BC1F2s flowered earlier than Jyothi and no individuals were found to flower as late as the donor parent. Except in case of days to flowering, the average estimates of yield attributes and yield of BC1F2s were less than that observed in the recurrent parent Jyothi, but higher than that observed in donor parent ISM. Two R gene pyramided BC1F2 individuals possessed white coloured decorticated kernels similar to the donor parent In spite of lower average estimates for yield attributes and yield, transgressive segregants were also observed among the BC1F2s. Negatively skewed platykurtic distribution was observed in traits like plant height, leaf length, panicle length, spikelets per panicle, grains per panicle, 100 grain weight, grain length and width, and decorticated kernel width, while positively skewed platykurtic distribution was evident for all other traits viz., days to flowering, total tillers, productive tillers, leaf width, and grain yield per plant. The decorticated kernel length was the only trait that exhibited a leptokurtic distribution and had registered negative skewness. Hence, it can be inferred that the trait kernel length is governed by a few segregating genes with majority of them exhibiting decreasing effects and dominance-based interactions. All the forty-two R-gene introgressed BC1F2s were selfed to yield seeds (3897 Nos.) of BC1F3 generation. The BC1F3 progenies of the 3-R-gene homozygotes need to be further backcrossed to the recurrent parent to aid higher recovery of the recurrent parent genome. This will eventually lead to the development of an Improved Jyothi with durable resistance to BB pathogen. These stable R-gene introgressions can also serve as donors in BB resistance breeding programmes in rice. In addition, the transgressive segregants could serve as potential breeding materials for development of high yielding genotypes.
Pyramiding of bacterial leaf blight resistance genes in rice variety jyothi (PTB 39) through marker assisted selection
(Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara, 2017) Kabade Pramod Gorakhanath; Rose Mary Francies
Seed invigoration for improved field performance and storability in ash gourd (benincasa hispida (thunb.) cogn.)
(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Bennett Thomas, K; Rose Mary Francies
Seed invigoration to overcome dormancy in ash gourd (Benincasa hispida (Thunb.) Cogn.)
(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2016) Shobha, K V; Rose Mary Francies