Evaluation of photothermic indexing in early, normal and late sowing dates in different rice genotypes

Abstract

Rice (Oryza sativa L.) is the main staple food of our country as well as two third of the world’s population. In Asia, it is feeding about 3.5 billion people which accounts for more than 90% of total rice production. Both biotic and abiotic factors affect the production of rice. Temperature and light have their simultaneous effects on the growth and development of the rice crop. For successful rice production, suitable transplanting dates can result into vigorous vegetative as well as reproductive growth. The response of rice genotypes to sowing date is very important when looking for the best varieties for a particular region. To understand physiological and biochemical basis of grain yield in rice (Oryza sativa L.) different rice varieties were grown in early (25th May), normal (12th June) and late sown (27th June) conditions and the field experiment was conducted at Norman E. Bourlog Crop Research Center, G. B. Pant University of Agriculture and Technology, Pantnagar during kharif season 2014 with different rice genotypes, namely, IET20924, IET22569, IET22580, IET23275, IET23299, IET23300, IET23324, PHY1, PHY2, PHY3, LALAT, MTU1010, PR113, SASYASREE and IR64. Differences of about fifteen days were kept in sowing dates of early, normal and late sown conditions. After critical analysis, it was observed that early sown condition was best suited for higher grain production because in early sown condition the crop gets more time for vegetative growth and a better light and temperature coordination for its strong establishment.