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20141
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Subject: Plant Breeding × End date: 2017 × Start date: 2010 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    GENETIC STUDIES ON HEAT TOLERANT TOMATO (Lycopersicon esculentum Mill.) AND THEIR ANDROGENIC RESPONSE TO ANTHER CULTURE
    (AAU, Jorhat, 2014) Das, Reecha T.; Talukdar, Pranab
    The present investigation comprising of parental, F1, F2 and backcross generations of four tomato crosses viz. H7997 x CLN1621E, H7997 x BL337, H7997 x Nagcarlan and H7997 x CLN2366A was conducted at Assam Agricultural University, Jorhat with three objectives- 1) to study the pattern of inheritance and gene effects for yield, yield attributing and physiological characters related to heat tolerance. 2) to study the genotype environment interaction of the generations of the crosses and 3) to study the androgenic ability of tomato lines and their hybrids. The experiment was conducted in three different environments during the offseason and one in the rabi season. Significant variation was revealed among the crosses and generations for almost all the yield and yield attributing and physiological characters. The pooled analysis of variance indicated profound influence of the environments on the expression of all the characters except for days from flowering to fruit setting. High estimates of genotypic coefficient of variation (GCV) was observed for fruit yield per plant and relative stress injury in most of the environments. High heritability with high genetic advance was observed for number of fruiting clusters per plant, fruit yield per plant, relative stress injury, pollen viability percentage and chlorophyll stability index in two or more environments. Out of the four crosses, high fruit yield per plant was recorded for three crosses viz. H7997 x CLN1621E, H7997 x Nagcarlan and H7997 x CLN2366A all were at par. Pooled analysis of variance for stability revealed significance of linear genotype - environment interaction for all the characters except for days from flowering to fruit setting and number of fruiting clusters per plant. Non linear genotype-environment interaction found to be significant for all the characters except for days from flowering to fruit setting, flower shed percent, chlorophyll stability index and relative stress injury. In the present investigation, the F1 of crosses H7997 x CLN1621E, H7997 x Nagcarlan and H7997 x CLN2366A and F2 of cross H7997 x CLN2366A and B2 of cross H7997 x BL 337 average stability for fruit yield per plant. Correlation studies between stability parameters of yield with yield attributing and physiological characters and also amongst them revealed that stability of and number of fruits per plant among the yield attributing characters and membrane stability percentage and chlorophyll stability index among the physiological characters together with plasticity of rest of the characters was mainly responsible for yield stability in heat tolerant tomato. F1 of cross H7997 x CLN1621E exhibited consistently significant mid parent heterosis over environments for most of the characters including fruit yield per plant. This was followed by crosses H7997 x Nagcarlan and H7997 x CLN2366A. Inheritance studies indicated failure of additive-dominance model for all yield and yield attributing and physiological characters In general, additive effect was found to be predominant in most of the yield attributing and physiological characters in almost all the crosses in two to three environments. Response of the components of generation mean to environmental fluctuations revealed that additive gene effect was consistent for number of primary branches per plant, days from flowering to fruit setting, number of fruiting clusters per plant and number of fruits per plant. Among physiological characters additive effects were found to be consistent for senescence index, lipid peroxidation and relative stress injury. Both additive and non additive gene effect was found to be consistent for fruit yield per plant. Duplicate epistasis was observed for most of the characters under study including fruit yield per plant. However, complementary epistasis was observed for days to fruit maturity, number of fruiting clusters per plant and fruit yield per plant in one to two crosses in individual environments. Androgenic studies revealed that H7997 x CLN 2366A and H7997 x Nagcarlan were the most responsive genotypes with high callus induction percentage and callus diameter. Thus there is also scope for development of doubled haploids in these two crosses.