Tolerance of Desmanthus spp. accesses to different water restriction intervals

Water deficit tolerant native legumes are a promising resource for increasing productive efficiency in livestock farming in dry regions. The aimed to evaluate the tolerance to the water deficit of Desmanthus spp. accesses by morphological, productive and chemical composition responses. Five accesses of Desmanthus spp. (7G, 31D, 8S, PNZ, and 13AU) were evaluated, which were submitted to four water restrictions (7, 14, 21, and 28 days). The experimental design was completely randomized, in factorial design 5 x 4 and five replications. The accesses 31D, 13AU e 7G had greater plant high, from 40.4 to 89.7 cm. However, the leaves amount, branches and leaf length were lower than accesses 8S and PNZ. Dry matter production and leaf/stem ratio were greater for accesses PNZ and 8S, reaching 3.7 and 3.6 g per pot, and 1.09 and 1.07, respectively. The 7-days water restriction produced 12 times more dry matter (8.1 g per pot) compared to the 28-days, with a decreasing linear effect. The leaf/stem ratio reduced from 1.0 (7 days) to 0.7 (28 days). Accession 8S showed lower mortality in water restriction for 21 and 28 days. The longer water restriction interval (28 days) resulted in lower protein (185 g kg-1) and condensed tannins (6 mg g-1) and higher fiber content (665 g.kg-1) compared to 7 days of water restriction, 238 g kg-1, 22 mg g-1 and 537 g kg-1, respectively. Water restriction promotes changes in the morphological and productive characteristics and chemical composition of the accessions, reducing protein and condensed tannins, but increasing fiber. The accesses PNZ and 8S have greater tolerance to water restriction.