Natural variation of top three leaf traits and their association with grain yield in rice hybrids

Abstract

A field experiment was conducted at Indian Institute of Rice Research farm, Rajendranagar, during the rainy (kharif) seasons of 2012 and 2014 to evaluate the association between leaf traits of top three leaves with grain yield. Among the top three leaves the length of 3rd leaf is more compared to 2nd and 1st leaf, whereas the width and the rate of photosynthesis was more in case of flag leaf compared to 2nd and 3rd leaf. The area was more in case of 2nd leaf compared to 1st and 3rd leaf, and leaf angle was more in case of 1st leaf, followed by 3rd and 2nd leaf. Leaf length was highest in case of flag and 2nd leaf in 24(K), PHB-71 and PA6444. Width of top three leaves and area of flag leaf and 2nd leaf were highest in case of DRRH 3, PHB-71 and RPHR-1005. Flag leaf angle was greater in case of 248 (S), PA6444 and DRRH3, whereas 2nd leaf angle was highest in PA6444, S-40, KRH 2 and PHB-71. The 3rd leaf angle was highest in case of KRH 2, PHB 71, 50-13 and S-40. Highest flag leaf thickness was recorded in 13-7, PHB-71 and PA6444. Photosynthetic rate and stomatal conductance of top three leaves was highest in KRH 2, PHB-71, 13-7 and DRRH 3. Highest grain yield was also observed in hybrids (KRH 2, PHB-71, 13-7 and DRRH 3), which exhibited a short and intermediate leaf length and leaf width, and leaf angles of any two leaves of top three leaves were erect or of intermediate types.