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2007 - 20102
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Subject: Genetics and Plant Breeding × Author: Bhaskar, Jitendra × Type: Thesis ×
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    ThesisItemOpen Access
    Correlation and path analysis in tea [Camellia sinensis (L). O. Kuntze]
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2007-06) Bhaskar, Jitendra; Roy, D.
    The field experiment was conducted on five varieties at Tea Research Station, Kausani, Uttarakhand to understand nature and magnitude of variation present among the tea germplasm and to characterize the different clones. Data were recorded on ten characters for each genotype. The phenotypic coefficient of variability was highest for surface area of bush followed by weight of the bud and number of plucking points but lowest for length of the 1st leaf of the shoot. Genotypic coefficient of variability was highest for surface area of bush followed by weight of the bud and number of plucking points and lowest for length of the 1st leaf of the shoot followed by width of 1st leaf of the shoot. 100 seed weight, length of mature leaf, weight of the bud and number of plucking points showed high heritability. The genetic advance was high for 100 seed weight followed by number of plucking points and weight of the shoot. Comparison of mean showed that T-78 Vs Kangrajat, BSS-449 Vs Kangrajat and UPASI-9 Vs Kangrajat, combinations are genetically diverse. Comparison of variance shows that AV-2 and Kangrajat are genetically diverse genotypes. Comparison of both mean and variance shows that AV-2 and kangrajat are genotypically most diverse genotypes. Correlation coefficients at the genotypic level reveal that only three pair of traits, namely, number of plucking points and weight of the shoot, surface area of bush and width of 1st leaf of the shoot, length of mature leaf and width of the mature leaf showed positive and significant phenotypic correlation. Surface area of bush showed negative and significant correlation with weight of the shoot. Path analysis revealed that only four traits, namely, length of the mature leaf, width of the mature leaf, number of plucking points, and width of the 1st leaf of shoot showed high, positive and direct effect on weight of the shoot. Correlation and path analysis revealed that in tea, traits, number of plucking points, length of mature leaf, width of mature leaf and width of 1st leaf of the shoot can be considered important for improving the weight of shoot in tea.
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    ThesisItemOpen Access
    Combining ability, heterosis and phenotypic stability for yield and other desirable characters in high quality protein maize (Zea mays L.)
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2010-08) Bhaskar, Jitendra; Verma, S.S.
    The present investigation was conducted during Kharif, 2009 at Norman E. Borlaug Crop Research Centre, Pantnagar under normal (recommended dose of nitrogen, E1), low-nitrogen(E2) and excess soil moisture (E3) environments with the objectives: (i) to identify superior single cross quality protein maize (QPM) hybrids, (ii) to determine nature and magnitude of heterosis, (iii) to estimate variability parameters, combining ability and phenotypic stability of parental inbreds and hybrids for important economic characters in quality protein maize (QPM). The experimental material consisted of 21 QPM inbred lines and 3 broad-base testers crossed in a line x tester fashion. All the 24 parents, 63 F1’s along with three checks HQPM-1, Shakti-1 and Pragati, were evaluated in a randomized complete block design. Observations on 15 characters, like plant height, ear height, 100-kernel weight, ear length, ear diameter, number of kernel rows/ear, number of kernels/row, number of nodes bearing brace roots, days to 50% tasselling, days to 50% silking, anthesis-silking interval, protein, tryptophan and lysine contents and grain yield were recorded. Analysis of variance revealed that these genotypes differed significantly for all the 15 characters, indicated the presence of sufficient amount of variability among genotypes. As regards heterosis, high per cent heterobeltiosis, standard heterosis and relative heterosis in all the three and pooled over environments was observed in crosses, L1×T1 (DQPMC-3(Y)_101-1-2-1-1×DMRQPM-03-106-#-_-1-1-1), L2×T1 (DQPMC-3(Y)_101-1-2-1-1×DMRQPM-03-103-#-_-2-1-1-1), L10×T1 (DQPMC-3(Y)_50-1-1-1-1×DMRQPM-03-106-#-_-1-1-1-1), L11×T3 (Pool 18C8(TEYFQPM)-B-9-1-1-1×Pool17C8(TEYFQPM)-B-57-2-1-1) and L14×T1 (DMRQPM-28-5-_-_-#-_3-_-1-1-1× DMRQPM-03-106-#-_-1-1-1) for grain yield. High estimates of heritability were observed for quality traits, 100-kernel weight and grain yield in all the three environments, whereas, high estimates of expected genetic advance as per cent of mean were recorded for grain yield and quality characters, under all the environments. Combining ability analysis revealed significant variances due to GCA and SCA for most of the characters in all the three environments indicating importance of both additive and non-additive genetic variances. The magnitude of SCA variance was greater than GCA variance for all the characters in all the environments showing preponderance of non-additive variance and suitability of material for hybrid breeding. The GCA effects of the parents indicated that parental lines, L1, L2, L3, L4 in E1; L1, L3, L4, L11, L12, L13, L14 and L16 in E2; L8, L4 and L7 in E3 and L1, L2 and L4 in pooled environment and testers, T1 and T3 in over all environments, were the best combiners. The maximum SCA effects were observed in crosses, L11×T3, L14×T1 and L3×T1 in E1, L11×T3, L17×T3 and L1×T1 in E2, L11×T3 in E3 and L11×T3 and L17×T3 in pooled environment for grain yield and its contributing traits as well as for quality traits. The pooled analysis of variance for phenotypic stability indicated that mean squares due to genotypes and environments were significant for most of the characters. It indicated substantial variability among genotypes and environments. G×E interaction was also highly significant for all the traits except quality characters. Among the 21 lines and 3 testers, L1, L4, L6, L10, L12, T1 and T2 showed desirable stability for grain yield and its components along with quality characters. Out of 63 single crosses, most desirable and stable were L2×T3, L3×T3, L5×T2, L5× T3, L7×T1, L7×T3, L8×T1, L8×T2, L8×T3, L9×T3, L10×T1, L10×T2, L11×T2, L11×T3, L12×T1, L12×T3, , L13×T3, L14×T3, L16×T2, L16×T3, L17×T2, L17×T3, L20×T2, L20×T3, L21×T1, L21×T2 and L21×T3 for grain yield. However, L1×T1, L1×T3, L2×T1, L2×T2, L3×T3, L4×T3, L6×T3, L8×T2, L10×T2, L10×T3, L11×T1, L14×T2, L15×T1, L16×T1, L16×T2, L16×T3, L17×T3 and L20×T3 were found to be desirable and stable for quality traits. For rich environment, L1, L2, L4, L9, L13 and L21, tester, T1 and T2 and crosses, L1×T1, L2×T1, L4×T3, L6×T1, L7×T3 and L11×T1 showed stable and desirable performance. However, under poor environment, L1, L8, L9, L13, L14 and L17, tester, T1 and T3 and crosses, L4×T2, L5×T2, L7×T2, L18×T3 and L19×T2 exhibited stable and desirable performance for grain yield and its contributing traits. While, for quality characters no specific cross was found good under both rich and poor environment.