|Shahsawar, M - UNIVERSITY OF IDAHO|
|Brown, J - UNIVERSITY OF IDAHO|
|Myers, J - UNIVERSITY OF IDAHO|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 30, 1994
Publication Date: N/A
Technical Abstract: Dry beans are often grown in soil-water limiting areas throughout the world. As in other C-3 crops, carbon isotope discrimination might be useful in screening dry bean cultivars for water-use efficiency or drought tolerance. In preparation for such research, we wished to characterize carbon isotope discrimination in seed as a function of environment (Kimberly 2 years and Parma, Idaho 1 yr), genotype, pod position, and seed size. Cultivars adapted to Idaho were field grown with water-adequate or water-stress treatments (50% of adequate water applied after flowering). Carbon isotope discrimination was affected by environments and was positively correlated with seed yield and biomass. Carbon isotope discrimination was reduced by water-stress treatments and reduced in later vs. earlier pod sets. Within pods, carbon isotope discrimination was not associated with seed size. Although genetic variation for carbon isotope discrimination was observed, variability among these cultivars was low. The narrow range in carbon isotope discrimination values suggests that additional cultivars with greater genetic variability must be sought before significant progress can be made in breeding for drought tolerance.