Production of legume seeds without irrigation

Célido Matías Ruiz

ABSTRACT
In two trials with randomized block design and four replications, the seed production potential of 18 cultivars from 11 tropical forage legumes without irrigation was studied. The cultivars studied in the first trial were: Teramnus labialis cvs. Semilla Clara and Semilla Oscura; Stylosanthes guianensis cvs. CIAT-184, CIAT-136 and Cook; Macroptilium atropurpureum cv. Siratro; Centrosema pubescens cv. CIAT-5172 and Lablab purpureus cv. Rongai. In the second essay the following cultivars were evaluated: Centrosema pubescens cvs. CIAT-482, CIAT-5151, CIAT-404 and IH-129; Centrosema acutifolium cv. CIAT-5112; Indigofera mucronata IH-301; Aeschynomene histrix CIAT-9666; Pueraria phaseoloides CIAT-9900; Desmanthus virgatus “Corralillo” and Desmodium distortum CNIA-249. All the cultivars studied in the first experiment showed a seed production potential that allows their propagation at commercial scale, although the highest yields of pure seed in the first year corresponded to T. labialis cv. Semilla Oscura (813 kg/ha and Semilla Clara (797 kg/ha). However, in the second year the highest seed yield (566,1 kg/ha) was obtained in L. purpureus cv. Rongai, without significant difference from T. labialis cv. Semilla Oscura, but it was higher than the other treatments; while C. pubescens CIAT-5172 and M. atropurpureum cv. Siratro did not produce seed because of the affectations caused by fungi and yellow scab. In the second trial the highest pure seed yields (1 024 kg/ha) in the first year corresponded to C. pubescens cv. CIAT-482, but all the cultivars showed high potential; while in the second year the highest production (518,1 kg/ha) was obtained in C. pubescens IH-129 and the lowest ones (0; 14,4; 44,3 and 92,7 kg/ha) in D. virgatus, C. acutifolium, P. phaseoloides and C. pubescens cv. CIAT-404, respectively. These low yields were influenced by severe attacks of Atta insularis in D. virgatus and by fungi in the other species. Seed germination was relatively low in all the cultivars due to dormancy, caused by the presence of hard seed coats, except in L. purpureus which showed high germination. It is concluded that it is possible to produce seeds of tropical forage legumes in Cuba without irrigation and with low fertilizer doses. In the first year the studied cultivars showed a sufficient seed production potential to be propagated at commercial scale; while in the second year, although the yields decreased, most cultivars showed good potential. The exceptions are D. virgatus, M. atropurpureum and C. pubescens CIAT-5172, which did not produce seed as a consequence of severe insect, fungus and yellow scab attacks, respectively.