Vol. 9, Special Issue 9, Part D (2025)

An investigation was carried out at experimental research farm of Wheat and Maize Research station, Parbhani during 2024-25. Fifty-three genotypes of maize were studied to characterize fifty-three maize inbred lines for their heat tolerance ability on the basis of morpho-physiological traits. These genotypes were evaluated during 2024-25 in randomized block design with two replications at experimental farm Wheat and Maize Research Station, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani (Maharashtra). Data was recorded for different heat stress related primary and secondary plant traits i.e. days to 50% tasseling, days to 50% silking, anthesis-silking interval, plant height, thousand grains weight, grains yield per plant, LAI, MSI and SCMR value. The result revealed based on performance of different inbred lines for day to 50% tassel genotype IMLSB 2037 and CML 74 were identified as heat tolerant. Genotype with lower days to 50% silking are generally early maturing which helps the plant to avoid heat stress. The lowest meant value of days to 50% silking was observed in genotype VS 143 during rabi. The genotype IMLSB 2037 and VS 143 were identified as highly tolerant to heat in case of days to 50% silking. The increase in ASI was less in genotype IMLSB 2013. In case of plant height and ear height the genotype EC 656087⊗⊗⊗⊗ were identified as highly tolerant to heat stress. The genotypes DML 1276, EC 655966(B) ⊗⊗⊗, IAMI 27-⊗⊗⊗, V1489-13 and VL172416 shows minimum reduction in case of thousand grains weight. In terms of grains yield per plant the genotype EC 656087(B)⊗⊗⊗ were identified as tolerant to high temperature.

Leaf area index significantly influenced by high temperature which reduced photosynthetic surface area and consequently the potential for yield reduced. The maximum leaf area index was observed in genotype VL172416 (2.76). The genotype EC 656087(B)⊗⊗⊗⊗ and VL172416 were identified as heat tolerant. SCMR value (chlorophyll reading) during rabi was maximum in genotype VL172416 (67.01) while, minimum in genotype IMLSB 537-2 (33.055). The genotype EC 656087⊗⊗⊗⊗ and VL172416 were identified as highly tolerant under heat stress. Membrane stability index reduced during high temperature due to increase kinetic energy of molecules across membrane. In genotype CM 144 the MSI reduction was more while, in 118760 it was less as compared to all other genotypes. The genotypes EC 672603⊗⊗⊗, IMLSB 2013, IMLSB 2166 and V1489-10 shows notable increase MSI as compared to kharif.