Browsing by Author "Sreekumar, S G"

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Breaking seed dormancy in pottavaga (Albyzzia Stipulata, Boivin)
(Kerala Agricultural University, 1978) Gopinathan Nair, N; Ramachandran Nair, N; Sreekumar, S G
Cause-effect relationship of cane and sugar yield components in sugarcane
(Kerala Agricultural University, 1989) Gopinathan Nair, V; Sreekumar, S G
The cause and effect relationship of cane and sugar yield components studied in the plant crop performance of 48 hybrid varieties revealed that circumference of cane, number of millable canes per plot and length of cane had high direct contributions for cane yield. Pol percentage at 12th month had maximum direct effect on CCS percentage. Among the two components contributing to sugar yield, cane yield had maximum contribution rather than CCS percentage, thereby suggesting that increasing the cane yield through its components like circumference of cane, number of millable canes or length of cane, the sugar yield can also be increased, through correlated response.
Cause-effect relationship of drought tolerant traits and grain yield in cowpea
(Kerala Agricultural University, 1997) Magic Mereena; Sreekumar, S G
Sixteen grain cowpea varieties were evaluated in a replicated field experiment at the College of Agriculture, Vellayani, Trivandrum. Estimation of cause and effect relationship of seven drought tolerant traits and grain yield revealed that varieties with high harvest index, leaf area index at vegetative period and long grain filling period will produce high grain yield under conditions of drought.
Combining ability for biological nitrogen fixation traits and yield components in black gram [Vigna mungo (L.) Hepper]
(Kerala Agricultural University, Vellanikara, 2001) Beena, Thomas; Sreekumar, S G
Twenty three black gram genotypes comprising of five lines with nitrogen fixing capacity, three high yielding testers and their 15 cross combinations were evaluated in randomized block design with three replications during summer 1995-96, at the Department of Plant Breeding and Genetics, College of Agriculture, Thiruvananthapuram. The best general combiners for important biological nitrogen fixation traits were COBG 305 and Pant U 19 among lines and T 9 among testers. Pant U 19 x T 9 was the best specific cross combination for the above traits. For number of pods and grain yield per plant, WBG 13 and T 9 were the best general combiners and hybrids, LEG 17 x VBN 1 and WBG 13 x AKU 4 were the best specific combinations
Combining ability for biological nitrogen fixation traits and yield components in blackgram (Vigna mungo (L.) Hepper)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1996) Beena Thomas; Sreekumar, S G
The research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1995-96. The objective was to assess the general and specific combining abilities and gene action involved in the inheritance of biological nitrogen fixation traits and yield components in blackgram, as a preliminary step for developing high yielding varieties with good biological nitrogen fixation capacity. The five lines, three testers and their 15 combinations were evaluated in a replicated field experiment and data on twelve characters were collected and subjected to line x tester analysis. The best general combiners for important biological nitrogen fixation traits were COBG305 and Pant U19 among lines and T9 among testers. The hybrid combination Pant U19 x T9 was the best specific combiner for these characters. In the case of number of pods and grain yield per plant, among. lines WBG-13 and among testers T9 were the best general combiners. The hybrids, LBG 17 x VBN 1 and WBG 13 x AKU4 were the best specific combinations for these traits. Considering the mean performance, sea effect and standard heterosis percentage Pant U 19 x T9 was identified as the best hybrid combination for nodule weight and nitrogen content at 50 per cent flowering. Regarding yield, the best hybrid was WBG 13 x AKU4. These superior combinations can be utilized further for developing improved blackgram varieties.
Combining ability for yield and drought tolerance in cowpea
(Department of Plant Breeding, College of Agriculture,Vellayani, 1993) Anilkumar, S G; Sreekumar, S G
A research programme was carried out at the Department of Plant Breeding, College of Agriculture, Vellayani during 1991 to 92 with five lines, three testers and their fifteen F1s'. The data on sixteen characters were collected and subjected to line x tester analysis for estimating combining ability and gene action in the inheritance of drought tolerance, yield and related characters. Analysis showed that the line DPLC-198 had a positive and significant gca for leaf area index, grain filling period, number of pods per plant, hundred seed weight, grian yield per plant and biological yield. The line IC-38956 showed negative and significant gca for duration upto first flowering and duration upto maturity. The line DPLC-216 had positive and significant gca for grain filling period and hundred seed weight. The line V-240 for number of seeds per pod and VCM-8 for duration upto maturity showed significant gca. The tester C-152 showed significant positive gca for number of seeds per pod, grain yield per plant and biological yield and showed significant gca for duration upto maturity. The tester Chharodi-1 showed significant negative gca for duration upto first flowering and duration upto maturity. The tester Kanakamany showed significant positive gca for grain filling period, hundred seed weight and biological yield. DPLC-198 x chharodi-1 and IC-38956 x C-152 showed significant and negative sca for duration upto first flowering while DPLC-198 x Kanakamany, IC-38356 x Chharodi-1 and VCM-8 x Kanakamany showed significant negative sca for duration upto maturity. Significant negative sca for proline content was recorded by IC-38956 x C-152, V-240 x Chharodi-1 and DPLC-216 x Kanakamany. DPLC-216 x C-152 and DPLC-216 x Kanakamany recorded significant positive sca for filling period. A significant positive sca for number of pods per plant, grain yield per plant and biological yield was recorded by DPLC-198 x C-152. Leaf area index, number of seeds per pod and hundred seed weight which had additive gene action can be improved by selection. Number of pods per plant and proline content had non-additive gene action.Presence of additive and non- additive gene action with preponderance of non-additive gene action was noticed for duration upto first flowering, duration upto maturity, grain yield per plant and biological yield while preponderance of additive gene action was noticed for grain filling period. The characters that are controlled by non-additive genes or predominantly under the control of non-additive gene can be improved by recurrent selection and recombination breeding. Based on the gca estimates the lines DPLC-198 and IC-38956 and the testers C-152 and Chharodi-1 and the hybrids such as DPLC-198 x C-152, DPLC-198 x Chharodi-1, IC-38956 x C-152 and IC-38956 x Chharodi-1 were recommended for further utilization. Exploitation of heterosis normally is not a viable proposition in cowpea in the absence of easy methods of large scale production of hybrid seeds.
Correlation studies in black gram under partially shaded conditions
(Kerala Agricultural University, 1992) Saji T Abraham; Sreekumar, S G; Saraswathy, P; Gopinathan Nair, V; Manikantan Nair, P
Effect of ethrel (2 chloro-ethyl phosphonic acid) on growth and yield of bhendi (Abelmoschus Esculentus L Moench)
(Kerala Agricultural University, 1979) Sreekumar, S G; Ramachandran Nair, N; Jayachandran, B K; Mary K George
Gamma ray induced economic mutations in groundnut
(Kerala Agricultural University, 1988) Gigi K John; Sreekumar, S G; Gopinathan Nair, V
Genetic analysis of bacterial blight (xanthomonas oryzae pv. oryzae ishiyama) resistance and yield in yice (oryza sativa L.)
(. Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2002) Devika, R; Sreekumar, S G
Genetic analysis of yield and its components in fodder maize
(Kerala Agricultural University, 1995) Sreekumar, S G; Suma Bai, D I
Nine fodder maize types were evaluated in a randomized block design with three replications during summer 1992 at the College of Agriculture, Vellayani under the AICRP (Forage Crops). Genetic analysis of fodder yield and its components revealed that plant height and plant population recorded high genotypic coefficient of variation, heritability and genetic advance indicating that selection based on these characters will result in improving fodder yield. Highest genotypic correlation was observed between green and dry fodder yield and also between plant population and dry fodder yield. High heritability and high genetic advance observed for plant height indicate additive gene action and the reliability of this character during selection programmes for improving the yield.
Genetic evaluation of pre-release cultures and varieties of rice for yield, sheath blight and sheath rot diseases
(Kerala Agricultural University, 1992) Sreekumar, S G; Gopinathan Nair, V; Balakrishnan Asan, R; Manikantan Nair, P
Genetic variability and correlations in cowpea Vigna Sinensis (L) savi
(Kerala Agricultural University, 1979) Sreekumar, S G; Ramachandran Nair, Y; Saraswthy, P; Mary K George; Thomas, E J
43 different genotypes of cowpea were grown in a Randomized block design with 2 replications during Khariff 1978. The different genetic parameters viz. coefficient of Phenotypic and genotypic variation, heritability in broad sense and genetic advance were calculated. The study revealed that all the characters showed positive phenotypic and genotypic correlations with yield. High heritability and genetic advance were noticed for 100 grain weight, yield of grain and yield of haulms. This indicate that selection based on the above characters will be very effective for the improvement of the crop.
Genetic variability in guinea grass
(Department of Plant Breeding, College of Agriculture, Vellayani, 1993) Shajan, V R; Sreekumar, S G
Thirty guinea grass clones were evaluated in a field experiment laid out in an RBD with two replications at the Instructional Farm, College of Agriculture, Vellayani during 1990. Data on nine biometric characters and fodder yield were collected and subjected to analysis of variance and co-variance. Genetic parameters like heritability, genetic advance and correlations were estimated. The path anlysis was done to assess the cause-effect relationship and discriminant function analysis was done to formulate selection index for identifying superior clones. The analysis of variance revealed significant difference with respect to all the characters except dry fodder yield. High genotypic and phenotypic variances were observed for number of panicles per hill, leaf length, and plant height. High phenotypic and genotypic coefficients of variation were observed for number of panicles per hill, weight of seeds per hill and leaf-stem ratio indicating the presence of large amount of genetic variability. High heritability estimates were recorded for the leaf length, number of panicles per hill, protein percentage, leaf-stem ratio, leaf breadth, weight of seeds per hill, number of tillers per hill, plant height and leaf area index. High heritability along with high genetic advance observed for number of panicles per hill, weight of seeds per hill, leaf-stem ratio number of tillers per hill, length, leaf area index and leaf breadth indicates additive gene action and the reliability of these characters during selection. High positive genotypic correlation and significant positive phenotypic correlations of green fodder yield with dry fodder yield, plant height, leaf length and leaf area index indicate that selection based on any one of these characters will result in the improvement of green fodder yield. The yield components showed varying degrees of association among themselves. Correlation studies indicate that selection based on plant height, leaf length and leaf breadth will be effective in the improvement of fodder yield. Path analysis revealed that leaf area index had the maximum direct effect on green fodder yield followed by plant height and leaf-stem ratio. Number of tillers per hill exerted negative direct effect on green fodder yield. Based on the results of variability, correlation and path analysis it can be concluded that selection based on plant height, leaf area index and leaf-stem ratio will be effective for the improvement of fodder yield in guinea grass. A selection index was constructed and by practicing twenty per cent selection, six top ranking clones viz. FR 42, MC 14, FR 559, Mackuenii, FR 550 and MC 16 were identified for use in future breeding programmes.
Genetic variability, path analysis and stability parameters in sugarcane
(Department of Plant Breeding, College of Agriculture, Vellayani, 1986) Sreekumar, S G; Gopinathan Nair, V
Investigations on genetic variability, path analysis and stability parameters wore conducted at the Sugarcane Research Station, Thiruvalla, Sugarcane Research Centre, Chittoor and Horticultural Research Station, Ambalavayal. The analysis of data collected from 48 clones evaluated at Thiruvalla revealed that the clones showed significant differences for all the 21 characters except Juiciness at 10th month in the first ratoon crop. The germination count on the 45th day, shoot count on the 180th day, number of late shoots at harvest, number of millable canes per plot, cane yield per plot and sugar yield per plot recorded moderate to high heritabiiity in the broad sense coupled with high genetic advance both in the plant and in the first ratoon crops indicating that selection based on these characters will be effective in improving cane and sugar yields. Correlation studies revealed that cane yield per plot had significant positive genotypic correlations with germination count on the 43th day, shoot count on the 180th day, number of millable canes per plot, cane weight and length of cane both in the plant and the first ratoon crops. Therefore, improvement in any one or more of these characters will result In a simultaneous improvement in the yiold of cane. Tho quality characters such as Juiciness, brix, pol and C.C.S. percentages at 12th month had positive but non-significant correlations with cane yield In ths plant crop and the first ratoon crop, suggesting difficulty in the simultaneous improvement of cane yield and quality characters through direct selection. The number of late shoots at harvest had highly significant positive genotypic and phenotypic correlations with the yield of cane in the first ratoon crop indicating that the number of late shoots at the time of harvest can be considered as a reliable criterion for the selection of clones with good yielding ability in the ratoon crop. Sugar yield recorded significant positive gonotypic correlations with cane yield and tho components of cane yield such as germination count on the 45th day, number of millable canes per plot, cane weight and length of cane. Sugar yiola also had significant positive genotypic correlations with brix, pol and C.C.S,percentages at 12th month, Tho significant positive gonotypic correlations of sugar yield with cane yield and its important components suggests that by increasing the cane yield, sugar yield per plot can be increased.
Genotype x environment interaction and stability of pre-release cultures and varieties of rice
(Kerala Agricultural University, 1993) Sreekumar, S G; Gopinathan Nair, V; Balakrishnan Asan, R
Stability analysis conducted using the data collected from nine genotypes of rice evaluated during IS)8."i, 84, 85, «7and 88 kharif seasons at the College of Agriculture, Vellayani revealed that .ill the nine genotypes were stable for height of the plant. With regard to tillers per plant, Cul.126 (Keinya) and I'avi/Jiom were stable. The genotypes Karthika, Asha, Pavizhom, Cul.25331 and Cul.126 (Kemya) were stable for sheath blight disease, while Karlhika, Cul.25331, Cul.l2(i(Remya) and Cul.4(Aaralhy) were stable for sheath rot disease. Regard ing the grain yield, Karlhika and Cul.4 (Aarathy) can be considered as stable genotypes, since they had higher yield than grand mean along with average response and non-significant deviation from regression.
Genotype X environment interaction and stability of pre-release cultures and varieties of rice
(Kerala Agricultural University, 1993) Sreekumar, S G; Gopinathan Nair, V; Balakrishnan Asan, R
Stability analysis conducted using the data collected from nine genotypes of rice evaluated during IS)8."i, 84, 85, «7and 88 kharif seasons at the College of Agriculture, Vellayani revealed that .ill the nine genotypes were stable for height of the plant. With regard to tillers per plant, Cul.126 (Keinya) and I'avi/Jiom were stable. The genotypes Karthika, Asha, Pavizhom, Cul.25331 and Cul.126 (Kemya) were stable for sheath blight disease, while Karlhika, Cul.25331, Cul.l2(i(Remya) and Cul.4(Aaralhy) were stable for sheath rot disease. Regard ing the grain yield, Karlhika and Cul.4 (Aarathy) can be considered as stable genotypes, since they had higher yield than grand mean along with average response and non-significant deviation from regression.
Gujarath cowpea 2 (Chharodi 1) - an ideal cowpea variety for intercropping in coconut garden
(Kerala Agricultural University, 1993) Sreekumar, S G; Gopinathan Nair, V; Balakrishnan Asan, R
Comparative yield trials were conducted with nine varieties of cowpea for three years during kharif in the interspaces of coconut garden at the Instructional Farm, Vellayani. Based on the comparative yield trials' result, Gujaralh Cowpea 2 (Chharodi 1) variety of cowpea was selected and advanced to farm trial at seven locations in Thiruvananlhapu ram district during kharif 1989 along with C 152 and local variety. The variety Gujarath Cowpea 2 (Chharodi 1), which recorded a highest grain yield in farm trials was recommended for cultivation in the interspaces of coconut garden in Thiruvananlhapuram district during kharif.
Heterosis in greengram
(Kerala Agricultural University, 1978) Sreekumar, S G; Abrahm, A T
Five elite strains (P. S. 7 X Madira, PLMB 9, Pusa Baisakhi, E.C 1653) and their 10 cross combinations were compared in an experiment adopting a randomised block design with 3 replications. The study revealed that parents showed {\ >< • ; cross compatibility. Significant positive heterotic vigour over better parent was exhibited for the number of leaves, number of pods, length of pod and grain yield. Negative heterosis was noticed in the case of 100 seed weight. The magnitude of heterosis varied in different parental combinations. The heterosis in yield noticed is through heterosis in yeild components viz. number of branches per plant, number of pods per plant and number of clusters per plant.
Induced mutagenesis for earliness in groundnut (Arachis hypogaea L.)
(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1987) Gigi, K John; Sreekumar, S G