GENETICS OF DROUGHT TOLERANCE IN MAIZE (Zea mays L.) UNDER DIFFERENT POTASSIUM LEVELS
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Date
2019
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Birsa Agricultural University, Ranchi
Abstract
Maize (Zea mays L.) is also known as the ‗Queen of Cereals‘ due to its wide applications in variety of products. It serves as the staple food for 900 million poor, 120 ‐140 million poor farm families, and about one‐third of all malnourished children globally. Due to increase in global food demands and consumer choices, maize is emerging as the wonder crop for many countries especially in developing countries like India. Use of recommended fertilizer facilitate good growth of maize crop plants, and in obtaining high yield. Along with nitrogen and phosphorus, potassium (K) is the macro element required by the plants for its various metabolic functions. K has its role in neutralization of organic acids formed during metabolism, enzyme activation, regulating leaf stomatal movement, and facilitating of photosynthate translocation. The knowledge of direction and magnitude of association between yield & its components and the relative importance of each factor involved in grain yield contribution, aids to the effectiveness of any breeding programme. The experiment was conducted with twenty genotypes to evaluate their performance under moisture stress condition at two doses of Potassium during kharif 2016 and rabi 2016-17. The materials used are four high productive female lines, three drought tolerant male lines used as tester and their twelve hybrids developed by Line x Tester mating design along with one check. The same set of genotypes has also been evaluated under irrigated field condition at same two different doses of Potassium as that of moisture stress condition of 50kPa at flowering and grain filling stage under rain out shelter. The genotypes evaluated under different moisture regime and K level showed that at increased dose of K there is earliness in traits like DT, DS, ASI at both field condition and moisture stress condition. Moisture stress condition causes longer days to flowering. Reduced ASI was observed at increased dose of K. Increases in K dose causes increase in PH, EH for all the genotypes under field condition as well as moisture stress condition. Increase in K dose causes increase in Stay Greenness under field condition as well as in moisture stress condition for all the genotypes. At increased does of K increase in no. of KR/Cob was observed at both field condition and under moisture stress condition for all the genotypes under study. Reduction in yield was observed at moisture stress condition at both level of K dose for all the genotypes. Among the hybrids, maximum reduction was recorded by H9 (45.29%) at field condition and at moisture stress condition also (43.02%). Among the
inbreds P7 (32.15%) shows maximum reduction at K1 dose and at K2 dose P3 (33.10%) shows maximum reduction.
The strip plot ANOVA showed significant differences were present among the genotypes for the traits DT, DS, DM, PH, EH, No. of leaves, LAI, LS, SG, LR, EL, KR/cob, K/row G/cob, SW, GY/ha, GY/plot, RL, RV. Significant differences was in case of K- level for all the characters studied except for leaf rolling. The interaction between genotypes and K-level was found significant for the characters DM, EH, GY/plot. At moisture stress condition during kharif season among the genotypes significant differences was found for all the traits except for ASI. Among the K-level significant differences was found for all the traits except for LR. The interaction between genotypes and K-level was found significant DM, EH, GY/plot. The Strip –Spilt ANOVA for quality traits of hybrids showed for significant differences among the moisture regime for all the quality parameters. Highly significant difference among the K – level was observed for carbohydrate content, Zn content. The interaction of moisture regime & K –level was significant for protein content, K content, Fe content & Zn content. Among the 12 hybrids, highly significant difference was observed for all the quality parameters. The interaction of moisture regime & genotype was highly significant for protein content, carbohydrate content, Fe content & Zn content. Significant differences was also observed for the interaction of K- level & Genotype. The interaction of all the three parameters, Moisture regime, K- level, & Genotype was also highly significant for all the quality parameters studied. Drought had negative effect on protein, carbohydrate, K content and grain yield. But, bioavailability of Fe and Zn content in grain increased under drought, which is very useful information for breeders. The hybrid H4 is superior performing so far with high carbohydrate, Fe content and an average grain yield under irrigated condition. Similarly, H3 is superior for protein, Zn and K content with average grain yield under drought condition. Based on percent disease index value. Most of the hybrids lies under the categories of moderately resistant at low dose of K and only one hybrids shows moderately susceptible but at higher K dose disease reaction gets improved for four hybrids viz., BAUIM-2 x HKI 1532, BAUIM-4 x HKI 1532, BAUIM-4 x HKI 577 from moderately resistant to resistant and for BAUIM-5 x HKI 335 the reaction changes from moderately susceptible to moderately resistant.
Description
GENETICS OF DROUGHT TOLERANCE IN MAIZE (Zea mays L.) UNDER DIFFERENT POTASSIUM LEVELS