Studies on genetic parameters and screening for callose mediated resistance for botrytis grey mould disease in chickpea cicer arietinum l

Abstract

The present investigation was conducted at N. E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, India, with the objectives to study the genetic parameters in diallel mating design and identification of BGM resistant genotypes through disease rating and Callose scoring. newlineIn the first experiment, eight parents including CSJ 515, P23, P37, RSG963, BG362, GNG1581, P87 and NN185 were crossed in diallel mating scheme and 28 crosses were produced. All the thirty-six genotypes were evaluated in randomized block design with two replications to estimate components of genetic variances, heritability, GCA and SCA effects and heterosis for thirteen yield and yield contributing traits. In the second experiment, screening of chickpea genotypes was done against Botrytis grey mould (BGM) disease in natural field condition for various morpho-physiological traits, estimation of genetic diversity by using hierarchical cluster analysis (HCA), genetics of variability parameters, correlation and path coefficient analysis. In the third experiment, screening for disease reaction in chickpea due to BGM invasion was examined. This experiment was carried out on the basis of callose deposition score using fluorescent microscopy and disease score in sick plot. newlinePresence of inherent genetic variability among parental genotypes and hybrids for all the thirteen traits was confirmed by analysis of variance of experimental design. Genetic component of variance of combining ability revealed the importance of both additive and non-additive gene actions for the traits under study. P 23 was good general combiner for most of the agronomic traits. Based on SCA and heterosis, RSG963 × GNG1581 was top cross for most of the yield contributing traits. newlineThe results of field screening against BGM disease revealed that out of 110 genotypes 6 chickpea genotypes exhibited disease rating range of 4.5-5 (moderately resistant). The analysis of variance for 13 quantitative characters during all the studied years revealed significant differences among genotypes for characters viz., plant height, number of primary branches per plant, first pod height (cm), number of pods per plant, 100 seed weight (g), biological yield per plant (g) and seed yield per plant (g), and also among blocks. Genetic diversity analysis based on HCA grouped the genotypes in 6 clusters respectively. High heritability coupled with high genetic advance as percent of mean was observed for number of pods per plant, number of seeds per pod, biological yield and seed yield. The seed yield per plant exhibited significant positive correlation with days to maturity. However a substantial negative association was found for the number of seeds per pod. Path coefficient analysis reveals that biological yield and harvest index followed by are the traits which show the high direct effects. newlineMicroscopic investigation showed that presence of callose deposits in the chickpea cell wall in response to BGM infection and it was the first report of callose accumulation due to BGM invasions in chickpea, as well as differences in these deposits were observed in the genotypes thereby callose score was devised to quantify the deposits. In the field screening, the response of genotypes was rated based on BGM symptoms. The three genotypes out of eight genotypes used in diallel analysis namely, CSJ 515, P23 and RSG963 and five genotypes viz., ICC14429, ICC12429, ICC14454, ICC14470 and ICC16376 out of 20 genotypes used in screening for disease reaction to BGM had higher callose scores and lower disease scores, which benefited their performance against infection. newlineThe utility of the crosses relies at extent of impact of enhancement in yield based on specific combining ability and heterosis over mid, better, and standard parents. Thus, present experiment will assist in the production of lines with a higher yield and improved disease resistance and it could be leveraged for further crop improvement programmes. newline