1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Morpho-molecular characterisation of D x D hybrids developed using 'annur', the dwarf ecotype of WCT coconut ( Cocos nucifera L.)(Department of plant breeding and genetics, College of Agriculture, Padannakkad, 2021) Anuprasad, T E; Sujatha, RCoconut is one of the most extensively grown crop in the world, playing a significant role in the economic, cultural, and social life of over 80 tropical countries. Coconut cultivars are classified into tall (variety typica) and dwarf (variety nana) types. Short statured palms are currently receiving more attention due to various socio-economic factors. However, the poor quality of nuts for various processing aspects and high susceptibility of dwarf palms to pest and diseases makes them unsuitable for large scale cultivation. The solution for this problem is development of suitable hybrids by combining the desirable features of tall and dwarf palms. West Coast Tall (WCT) is the most widely cultivated variety in Kerala and several ecotypes of WCT were reported. In a study initiated in 2005 at RARS Pilicode, an ecotype of WCT was detected in Annur, a place in Kannur district which showed dwarfing nature with nut qualities similar to WCT. The Annur ecotype was crossed in 2007-08 with the dwarf cultivars Malayan Yellow Dwarf (MYD) and Gangabondam (GB). The hybrid seed nuts along with interse seed nuts of Annur were planted at RARS Pilicode in 2009. The first flowering was recorded in 2014. The present study aims at evaluation of plant stature, yield, nut quality and other important morphological traits of Annur and the hybrids developed from it. The interse of Annur, Annur x GB and Annur x MYD were compared with corresponding characters of the respective parents as well as WCT, Keraganga (WCT x GB) and Kerasree (WCT x MYD). Significant reduction in height was observed for hybrids viz. Annur x MYD (2.251 m) and Annur x GB (2.065 m) which was on par with Annur (2.725 m) and considerably lower than the corresponding values of dwarf cultivars viz., MYD (5.2 m) and GB (8.885 m). Number of nuts per palm per year was on par in Annur (58.2) and Annur x MYD (55.4) while that was lower in hybrid Annur x GB (34.3). However, since the palms started flowering only in 2014, stabilization of yield is not attained. Nut weight and kernel thickness were significantly higher in Annur x MYD whereas these were on par in Annurand Annur x GB. Copra content in Annur and both hybrids were on par. In general, Annur x MYD showed superior performance for nut characters compared to Annur x GB. Annur palms were significantly similar to WCT for most of the characters except height, rate of leaf production, nuts per bunch, nut water content. When the yield of hybrids of Annur were compared with the standard check varieties viz., Keraganga (WCT x GB) and Kerasree (WCT x MYD), (101.5 and 104.25 nuts per palm per year) yield of Annur x GB and Annur x MYD were low. However, both hybrids showed nut characters similar to the respective released varieties ie, Annur x GB was similar to Keraganga and Annur x MYD showed similar nut characters with Kerasree except copra content (161.432 g and 193 g respectively). Better palms from each cross were analysed and palm numbers 1, 2, 15, 19, 20 and 28 were identified as better palms from interse of Annur. The better performing palms of hybrid, Annur x MYD were palm numbers 43, 44, 47 and 49. Three palms from Annur x GB (palm numbers 53, 55 and 56) were identified as better palms. Correlation analysis revealed significant positive genotypic correlation of nut yield per palm with all reproductive and yield characters and with most of vegetative and nut characters. Path coefficient analysis showed high positive direct effect on number of female flowers per inflorescence, number of bunches per palm per year, number of nuts per bunch, pole to pole circumference of nut, nut weight (with husk), shell and meat weight, quantity of liquid endosperm and copra content. High heritability coupled with high genetic advance was exhibited by the characters height of palm, leaf length, number of green leaves, number of inflorescences at the time of observation and number of female flowers per inflorescence. This indicates that these characters are governed by additive gene action and selection based on these characters will be effective. For both hybrids, height of the palm showed negative heterosis which indicates the dwarf nature of the hybrids. In hybrid Annur x MYD, most of nut charactersshowed heterosis over mid parent (relative heterosis) and better parent (heterobeltiosis). The standard heterosis was significant when compared with Keraganga but was not significant with Kerasree. Molecular characterization of the Annur (interse) and the hybrids from it was also attempted using Simple Sequence Repeat markers (SSR). Good quality genomic DNA is the prerequisite for any molecular work. DNA was isolated from all the parental palms as well as check cultivar Kerasree. The quality and quantity of genomic DNA obtained was verified using agarose gel electrophoresis and spectrophotometer. The quantity of DNA samples ranged from 350 to 1300 ng/μl with good quality. Screening of SSR markers for parents and check palms revealed polymorphism for the primers CAC02, CAC11, CNZ40, CnCirA9, CnCirB12, CnCirC3, CnCirC5, CnCirC7, CnCirE2, CnCirE12, CnCirF2, CnCirG11, CnCirH4 and CnCirH7. Out of 34 SSR markers, 27 were monomorphic between WCT and interse of Annur. Genetic Similarity analysis using the SSR markers revealed the high similarity between of interse palms of Annur and WCT. Dwarf palms viz. MYD and GB also showed high genetic similarity with each other. The present study revealed that the genotype Annur is a dwarf ecotype of WCT with similar nut quality and hence is a very promising genotype for breeding for dwarfness. The hybridization of ecotype Annur with MYD is found to be superior in yield characters compared to the hybridization with Gangabondam. However, both hybrids inherited the short stature from Annur and are promising. Since the yield characters needs to be stabilized, evaluation based on important vegetative and reproductive characters as well as molecular fingerprinting needs to be continued inorder to identify the full potential of these dwarf hybrids.Item Assessment of water stress tolerence in selectively fertilized coconut (cocos nucifera L.) hybrids(Department of Plant Physiology, College of Agriculture, Vellayani, 2018) Rahul Gupta, K; Roy StephenItem Standardisation of preservation techniques of coconut (Cocos nucifera L.) palm wood(Department of Wood Science, College of Forestry, 2017) Jeeshma, V J; Anoop, E VCoconut (cocos nucifera L.) palm wood belongs to the class of perishable timbers which can be used as an alternative wood sources with affective preservation. Preservative treatment of coconut wood can enhance the service life of coconut service life of coconut wood. The objective of this study was to develop appropriate preservative methods to treat sawn coconut wood under the prevailing eco-climatic conditions in Kerala and to evaluate the effect of different factors on the treatability of coconut wood. Wood samples were treated with inorganic (Copper Chrome Boron- CCB and Borax Boric Acid-BBA) and organic preservatives (Cashew Nut Shell (CNS) liquid, need oil and turpentine). Diffusion and pressure treatment were deployed for inorganic preservation and organic preservatives were investigated only through diffusion treatment. Wood samples were air dried to a moisture content of about 50 per cent and total of 354 sampled belonging to high and medium density wood were treated with preservatives. Diffusion treatment of inorganic preservatives in high and medium density wood showed no significant difference in retention whereas significant difference was observed for penetration percentage. For pressure treatment, retention and penetration were significant in high density wood whereas medium density wood showed only significant retention. A proportionate relation existed between the solution concentrations and the two observations- overall retention and penetration percentage. Relation of diffusion period and retention in high density wood showed no uniform pattern while, an increasing trend was seen in medium density wood. Penetration depth followed an increasing pattern under increasing treatment duration in the two density classes. Among the two treatment methods, pressure treatment performed better than diffusion treatment. Absorption percentage of organic preservatives was non-significant among treatment factors (chemicals and duration), and their interaction in the two density classes. The study found that sawn coconut wood samples could be effectively treated with preservatives complying with the prescribed retention and penetration percentages as per the different standards and therefore, could be used as a potential substitute for conventional timbers.