Genotypic variations in photosynthetic rate and respiratory losses in some grain legumes

The relative rate of photosynthesis in 12 genotypes of Cajanus cajan as measured by 14CO2 fixation, ranged from 100 percent in Pant A-2 to 126 percent in UPA 120. 14CO2 fixation was not related to specific leaf weight. Respiratory losses in the 20-day period after exposure were 63 and 51 percent respectively, in seedlings of UPA-120 and Prabhat cultivars. The relative rate of photosynthesis in 13 genotypes of Vigna aureus ranged from 100 percent in LM-646 to 196 percent in LM-205. PS-16 also showed high photosynthetic rate. The translocation of 14C from leaves, stems and petioles to reproductive organs Baisakhi accumulated larger proportion of total 14C in grain and showed lower respiratory loss than PS-16. The relative rate of photosynthesis in 20 Cicer arietinum cultivars ranged from 100 percent in S-330-1 to 224 percent in L-550. There was a considerable contribution from pod and stem towards total photosynthesis. (author)