Abstract
Northeastern Himalayan Region (NEHR) of India having frail landscape with unique climate, high rainfall with orography led wide spatio-temporal variation, often occurrence of droughts,terminal heat and high cloud covers causes antagonistic relationship with solar radiation. Growing of low yielding traditional genotypes susceptible to abiotic stresses including low radiation-use efficiency further decreased the productivity (<1.5 t/ha) of rainfed maize (Zea mays L.) in this region. The region needs improved genotypes to overcome these shortfalls. In present study, a field experiment was conducted during 2012 and 2013 to evaluate the performance of 15 improved genotypes and compared with popular traditional genotypes for physiological indices, radiation-use efficiency and finally, correlated with productivity. Results revealed that amongst the improved genotypes, hybrids Vivek QPM 9 followed by Prakash recorded significantly (P<0.05) higher physiological attributes and grain yield (4 860-5 055 kg/ha), which was two folds higher than the local genotype Chakhaochujak (hill) (2 081-2 113 kg/ha). Similarly, few other hybrids (HQPM 7, BIO 9681, PMH 1, PMH 4 and HM 4) also recorded significantly (P<0.05) higher (48 to 126%) grain yield over local genotypes. Estimated radiation-use efficiency indices (pheno- and helio-thermal, heat use efficiency) were significantly (P<0.05) higher in hybrids compared to local genotypes. Exploring improved genotypes suitable to rainfed hilly ecosystem, thus, promises improvement of maize productivity vis-a-vis food and livelihood security in the NEHR of India and other similar agro-ecological regions.