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ThesisItem Open Access Genetic evaluation of F2 generation of intervarietal crosses in greengram (vigna radiata (L.) wilczek(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2001) Leenamol, M A; KAU; Kamalam, NA research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2000-2001 with the objective of assessing the potential of F2 progenies of greengram in terms of variability and correlation with respect to yield, yield attributes and shade tolerance. Fifteen F 2 progenies derived from intervarietal crosses were evaluated under the partial shade of coconut garden adopting a randomised block design with three replications. Data collected for seventeen characters were subjected to statistical analysis. Coefficient of variation, heritability, genetic advance, correlation and path coefficients were estimated. The 15 F 2 progenies revealed significant difference for all the characters. However, measurement of periodical shade intensity did not show significant difference among the plots indicating the prevalence of uniform shade. Phenotypic and genotypic coefficient of variation were high for grain yield, leaf area index, number of pods per plant, photosynthetic efficiency, harvest index and 100 seed weight. High heritability coupled with high genetic advance was observed for harvest index, grain yield, number of pods per plant, 100 seed weight and photosynthetic efficiency. Correlation studies indicated that the characters leaf area index, . photosynthetic efficiency, number of seeds per pod, 100 seed weight and harvest index exhibited significant positive correlation with grain yield whereas days to 50 per cent flowering and days to maturity recorded significant negative correlation. Among yield components, photosynthetic efficiency and harvest index exhibited significant positive correlation with number of seeds per pod and 100 seed weight. Photosynthetic efficiency exhibited the highest positive direct effect on grain yield followed by harvest index. Negative direct effect on grain yield was recorded for number of seeds per pod, days to maturity and days to 50 per cent flowering. It can be concluded from the present study that under partially shaded condition, photosynthetic efficiency and harvest index are the most important yield components which can serve as selection criteria for better yield in greengram. Accordingly the genotypes T 7 (Ganga 4 x Pusa Baisakhi), T 5 (LGG 460 x Philippines), T I (IIPRM 3 x Philippines), T 2 (Ganga 4 x Philippines) and TI4 (RMG 353 x CO-2) and Tlo (LGG 460 x Pusa Baisakhi) may be selected for further work.ThesisItem Open Access Combining ability for shade tolerence and yield in greengram grown under coconuts(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2001) Preeta Liz, Korah; KAU; Kamalam, NThe current research programme on "Combining ability for shade tolerance and yield in greengram (Vigna radiata (L.) Wilczek) grown under coconuts" was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 1998-2000. The objectives were estimation of gene action, combining ability effects of parents and hybrids and heterosis. The experimental material consisted of five lines, three testers and their fifteen hybrids. Analysis of variance revealed significant differences among the genotypes for all the eleven characters subjected to statistical analysis except height of plants and shade intensity. The genotypes L3 (MGG. 314), Ls (LGG. 460) and T3 (CO.2» were superior in mean performance for yield and most of the yield attributes. The hybrids Ls x T 2 (LGG. 460 x Pusa baisakhii and L1 x T3 (IIPRM.3 x CO.2) were superior in mean performance for yield, pod characters, photosynthetic efficiency and tolerance to pod bug infestation. Non-additive gene action predominated for all the nine characters showing significant differences among the treatments. Ls (LGG. 460) and T 2 (Pusa baisakhi) were the best general combiners for yield and 2 length of pod while L) (IIPRM.3) was the best combiner for crop duration, pods per plant and photosynthetic efficiency. The hybrid L) x T 3 (IIPRM. 3 x CO.2) was the best specific combiner for yield. Significant heterosis was observed for all the characters studied. Ls x T 2 (LGG. 460 x Pusa baisakhi) showed maximum relative heterosis and heterobeltiosis for yield and pod length whereas L) x T 3 (IIPRM.3 x CO.2) showed maximum heterosis over mid parent and better parent for days to 50 per cent flowering, days to final harvest, pods per plant and photosynthetic efficiency. Combining the mean performance, sca effects and heterosis, Ls x T 2 (LGG. 460 x Pusa baisakhi) and L) x T 3 (IIPRM.3 x CO.2) were identified as superior crosses in terms of yield and yield attributes. The hybrid L) x T 3 (IIPRM.3 x CO.2) was also superior for days to 50 per cent flowering, days to final harvest and photosynthetic efficiency.ThesisItem Open Access Physiological genetics of character associations in hybrid rice(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2001) Sindhu, V K; KAU; Nandini, KThe studies were conducted at the College of Horticulture, Vellanikara, to analyse the "Physiological Genetics of character associations in Hybrid rice (Oryza Sativa L.) ". The study mainly aims to characterize the morpho- metabolic associations in plant attributes that contribute to higher productivity in hybrid rice. Three hybrids and their parental genotypes were evaluated to. understand how different genotypes may compliment one another physiologically and also to identify the stages at which the better physiological efficiency contribute heterosis. From this study, it was revealed that the heterotic advantages result in two ways VlZ., generalized morphologic improvement in growth and yield attributes and efficiency enhancement. The results also envisages the importance of heterotic functional efficiency over morphological efficiency. The stability of chlorophyll aJb ratio and the differential changes of Nrase enzyme activity, both at different phenophases shall serve as a better index for selection of genotypes in rice breeding programme. The pattern of biochemical character like soluble protein, enzymes like Peroxidase, catalase revealed that the magnitude of physiological expression is independent of genetic 'capabilities or genetic expressivity is conditioned by physiology of the plant. The soluble protein and enzyme activity at tillering phase appears to be the most critical in deciding the yield of the rice, in order to achieve a complete heterotic effect' in rice breeding. The biochemical as well as physiological aspects at different growing stages should be given due importanceThesisItem Open Access Genetic variability in chilli(Capsicum annuum L.) with emphasis to reaction to leaf curl virus(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2001) Leaya, Jose; KAU; Abdul Khadar, K MThe present investigation entitled "Genetic variability in chilli (Capsicum annuum L.) with emphasis to reaction to leaf curl virus" was conducted at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2000-2001. The data for the investigation were collected from two field experiments, each laid out in Randomised Block Design with three replications. The second experiment was conducted without taking any control measures against leaf curl virus. The 37 genotypes included in the study showed significant difference for all the 15 traits. The maximum values for phenotypic coefficient of variation (pC V) genotypic coefficient of variation (GC V) were recorded for fruit yield per plant and the minimum values for crop duration. PCV and GCV were high for fruit yield per plant, number of fruits per plant, average fruit weight, vulnerability index, fruit girth and number of flowers per plant. These traits also showed high heritability coupled with high genetic advance. Yield per plant was positively correlated with number offruits per plant, average fruit weight, number of secondary branches, number of flowers per plant, fruiting span and crop duration. Path analysis revealed high positive direct effect for average fruit weight, number of fruits per plant and crop duration. Hence selection for these traits can improve yield. The 37 genotypes were grouped into four clusters based on Mahalanobis D2 statistic. Cluster I was largest with 23 genotypes while cluster IV had only one genotype. Cluster n had eight and cluster III had five cultivars respectively. Cluster IV containing a single variety was superior to the other clusters in respect of desirable characters. Field screening of the 37 cultivars for leaf curl resistance (experiment Il) showed that eight genotypes were tolerant to the disease while 27 were susceptible and two were highly susceptible to the disease. Comparison of yield and vulnerability index in both experiments showed that reduction in yield was less in tolerant varieties than in susceptible ones. The performance of T 26, T 3 and T 13 were comparable under controlled and uncontrolled conditions. The genotype T 13 was identified as a desirable accession as it produced high yields inspite of the disease. Correlation analysis showed negative association of yield with vulnerability index in both experiments indicating that susceptibility to the disease leads to a reduction in yield. The high yielding types and leaf curl tolerant types identified from the study could be used as parents in crop improvement programme to evolve high yielding leaf curl tolerant varieties.ThesisItem Open Access Evaluation of brinjal (Solanum melongena L.) genotypes for yield and resistance to shoot and fruit borer (Leucinodes orbonalis Guen.)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2001) Daliya, T; KAU; Wilson, DThe present investigation on evaluation of yield and resistance to shoot and fruit borer of brinjal genotypes was conducted at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, during the period 2000 - 2001. Data for the study was collected from two field experiments. For the evaluation of yield and its component characters of the 25 brinjal genotypes, a field experiment was conducted in randomised block design with three replications. Analysis of variance revealed significant difference among the genotypes for all the characters studied. Grouping of genotypes revealed that the genotypes VI (Swetha), V2 (Surya) and V18 (Pusa Purple Cluster) were better as far as yield per plant, number of fruits per plant and number of harvests were concerned. Pus a Kranti (V 17) had better fruit length, girth and weight. High phenotypic coefficient of variation and genotypic coefficient of variation were observed for yield per plant, number of fruits per plant, number of harvests, number of leaves per plant and number of secondary branches per plant. High heritability coupled with high genetic advance was also observed for these characters. At genotypic level, yield per plant showed high positive correlation with number of harvests, number of fruits per plant and fruit weight. The path analysis showed that number of harvests, fruit weight and number of fruits per plant were the characters having high direct effect on yield per plant. The genotypes VI8 (Pusa Purple Cluster) followed by VI7 (Pusa Kranti), V21 (Brinjal Suphal), VI (Swetha) and V16 (Venganoor local) were having the highest index values. For screening of brinjal genotypes for resistance to shoot and fruit borer, a field experiment was laid out in randomised block design with two replications. All the 25 genotypes were significantly different for all the damage parameters. The genotypes V3 (CO-2), V17 (Pusa Kranti), V19 (Ark a Kusumkar) and V24 (Manjarigota local) came under the less susceptible category for all the damage parameters viz., percentage of plants infested, percentage of shoots infested and percentage of damaged fruits. The correlation studies on damage parameters revealed high positive correlation of number of bore holes per fruit with percentage of plants infested and percentage of shoots infested, while these damage parameters did not show correlation with percentage of damaged fruits. Percentage of damaged fruits showed high correlation with number of larvae per fruit. Cluster analysis based on different damage parameters and the yield obtained from the yield evaluation experiment enabled to group the genotypes into five clusters. The clusters Il and III were having the less susceptible genotypes viz., V3 (CO-2), V 17 (Pusa Kranti), V19 (Arka Kusumkar) and V24 (Manjarigota local) would be useful as parents for developing shoot and fruit borer resistant varieties. Cluster IV had the high yielding genotypes viz., VI (Swetha) and V 18 (Pusa Purple Cluster). So hybridization programmes using genotypes from these three clusters could lead to the production of high yielding varieties with high level of shoot and fruit borer resistance. Based on the superior yield performance and low level of susceptibility to shoot and fruit borer, the genotype VI7 (Pusa Kranti) was found to be suitable for cultivation in borer endemic areas. Genotypes which showed high yield and those showed less susceptibility to shoot and fruit borer attack could be used in developing better yielding varieties with resistance to shoot and fruit borer.ThesisItem Open Access Variability and path analysis in bush type vegetable cowpea(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2001) Ajith, P M; KAU; Sunny K, OommenThe present investigation aimed at evaluation of variability for yield and its association with yield related characters along with their direct and indirect influence on yield was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. Data for the study was generated from a field experiment conducted during the period 2000-2001. Twenty genotypes of bush type vegetable cowpea which included six improved varieties and 14 local cultivars were evaluated for yield and related characters in a field experiment in randomised block design with three replications. Analysis of variance revealed high variability among the genotypes for all the characters studied viz., days to 50 per cent flowering, number of days to first harvest, length of harvest period, duration, length of main stem, number of primary branches, number of pod clusters per plant, number of pods per cluster, number of pods per plant, pod length, pod girth, pod weight, number of seeds per pod and yield of green pods per plant. High phenotypic arid genotypic coefficients of variation were observed for length of main stem, number of primary branches and pod weight. The variety Vu 6 (Arka Garima) recorded the highest vegetable pod yield and pod weight. Vu 1 (Arka Suman) recorded the highest number of pods per plant. High heritability along with high genetic advance was seen for all the characters considered. Pod yield per plant showed high positive genotypic correlation with number of pods per plant, pod weight, number of pods per cluster, number of pod clusters per plant and pod girth. Path analysis revealed that number of pods per plant and pod weight were the main yield contributing characters due to their high direct effect on pod yield.
