Gene Action, inheritance studies and QTL detection for some morphological traits in lentil (Lens culinaris Medikus)

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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
The present investigation was carried out in rabi seasons during 2013-14, 2014-15 and 2015-16 at N. E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India, with the objectives to assess genetic variability, inter-character association and their direct and indirect effects, genetic divergence, gene action, inheritance studies and QTL detection for some morphological traits. Genetic variability, inter-character association, path coefficient analysis and genetic divergence were studied in 48 lentil genotypes and analysis of variance revealed that sufficient variability was present among genotypes under study. In general, PCV estimates were higher than the corresponding GCV estimates indicating the influence of environment. Moderate to high GCV together with high heritability estimate and high genetic advance as per cent of mean were oberved for seed yield per plant, harvest index and 100-seed weight. Correlation and path coefficient analysis suggested that biological yield per plot and harvest index had high significant phenotypic association and direct effects on seed yield. Therefore, direct selection for these two traits will bring desirable change in seed yield per plot. D2- analysis classified entire genotypes under study into 16 different clusters and cluster VIII was largest with 8 genotypes. Inter-cluster distance was maximum between cluster II and X hence, genotypes from these clusters will give high heterosis and generate variability if crossed together. Seed diameter contributed maximum towards divergence and this was followed by 100- seed weight, harvest index and number of pods per cluster. Generation mean analysis was carried out for three crosses i.e, PL 7 x PL 4, PL 7 x PL 406 and PL 7 x PL 8 and the experimental material consisted of six generations as P1, P2, F1, F2, BC1 and BC2. Thirteen morphological traits were studied to decipher the gene action in lentil. Epistatic gene interaction was found in all the three crosses for number of days to 50 % flowering, number of primary branches per plant, 100- seed weight, seed diameter, biological yield per plant and harvest index. Whereas, for rest of the traits epistasis was present in either one or two crosses only. Epistatic gene interaction along with presence of duplicate gene action was observed for most of the traits including seed yield per plant which suggested for the selection to be used in advance segregating generations. However, complementary gene interaction was observed in cross PL 7 x PL 4 for number of days to maturity, number of primary branches per plant, number of pods per plant and seed diameter. Inheritance studies revealed that rust resistance was dominant and monogenic in inheritance. Complementation for the rust resistance revealed that resistant parent PL 7 and PL 6 had different allele for resistance. Cotyledon colour in lentil was controlled by single gene and pink cotyledon colour was dominant over orange and yellow. Single gene controls the testa mottling in lentil and mottling is dominant over non-mottling. Molecular diversity analysis in 48 lentil varieties/advance lines using 27 polymorphic SSR markers resulted in amplification of 133 alleles. SSR 66 was most informative marker as it recorded maximum PIC value of 0.933 and can be utilized for diversity analysis in lentil. Based on Jaccards similarity coefficients, UPGMA ordered the population of 48 genotypes in to nine clusters. Cluster- III was largest and it was formed at similarity coefficient of 0.32 and it consisted of nine genotypes (PL 038, PL 153, LL 875, IC 201648, L 4188, IC 207709, L 4147, PL 028 and PL 046) followed by cluster- II (K 75, PL029, PL 7, KLS 218, PL 015, DPL 58, IC 201738 and PL 4), cluster- IV (PL 6, FLIP 96-51, DPL 15, IC201675, LL864, PL 5, PL 406 and PL 9.), cluster- V (ICC279032, PL 242, PL244, IPL406, PL225, PL227, PL239 and PL639), cluster- VI (PL 234, PL164, L 4148, PL210, DPL62, PL213 and PL220), cluster- I (IC201627, PL 017, PL 8 and PL 056), cluster IX (PL 221 and LH 84-8), cluster- VII (LL 931) and cluster- VIII (PL 218). Bulk segregant analysis revealed that SSR 204 showed polymorphism for bulks and parents and subjected to single marker analysis for 100- seed weight and seed diameter. Major QTL with marker SSR 204 was found for both seed size and seed diameter and it explains 33.06 % and 32.17 % phenotypic variation for both the traits, respectively.