Assessment of water use efficiency in single and multi-cut lines of berseem (Trifolium alexandrinum L.)

Abstract

Water use efficiency (WUE) and biomass yield were evaluated in released berseem varieties and breeding lines. The study included single-cut variety JBSC-1, three multi-cut varieties (Wardan, Bundel Berseem-2, Bundel Berseem-3), six single-cut lines (NU/7/5/15, NU/2/14/2015, NU/2/19/2015, NU/2/23/2015, Ex-8, FAO5), and four multi-cut lines (IL-16-1, IL-16-2, IL-16-3, IL-13-106), grown under pot conditions. Daily plant water requirements were recorded after 10, 20, and 40 consecutive days of irrigation, corresponding to 20, 30, and 40 days after sowing. Among multi-cut lines, IL-16-1 (3.4 g fwt plant-¹ kg-¹ water) and IL-13-106 (3.2 g fwt plant-¹ kg-¹ water) exhibited the highest WUE, whereas among single-cut lines, NU/2/19/2015 (12.8 g fwt plant-¹ kg-¹ water) and NU/2/14/2015 (12.2 g fwt plant-¹ kg-¹ water) showed superior performance. A significant positive correlation (p < 0.05, p < 0.01) was observed among all photosynthetic pigments. The levels of photosynthetic pigments, relative water content, and membrane stability index showed contrasting associations with green fodder yield, negative in multi-cut and positive in single-cut genotypes. Significant differences (p <0.05, p <0.01) were detected in plant height and dry fodder yield across the evaluated varieties. WUE, assessed on both a fresh and dry matter basis, exhibited a negative association. Notably, the single-cut variety JBSC-1 recorded the highest dry-matter-based WUE (0.23 g dwt plant-¹ kg-¹ water at 10 days) among all varieties tested.