Agronomic evaluation of new varieties of Pennisetum purpureum under drought conditions in the Cauto Valley

Dalibia Díaz Fonseca

ABSTRACT
In a zone of intense seasonal drought the agronomic evaluation was developed, in a randomized block design, of ten new varieties of Pennisetum purpureum obtained by tissue culture with resistance to drought from CT-115, which was used as Control. The new varieties were: CT-600, CT-601, CT-602, CT-603, CT-604, CT-605, CT-606, CT-607, CT-608, CT-609. The experimental scheme was developed in two stages, one of establishment and the other of cutting, in order to evaluate the agronomic performance of the new varieties under drought conditions. In the establishment stage, the highest sprouting capacity was reached in varieties CT-603 and CT-608 which exceeded 60 % at 29 days. In the establishment cut, no differences were found in the DM yield; however, the biomass structure varied, with a decrease of the leaf DM yield in CT-606. In the cutting stage, the varieties CT-603, CT-608 and Control showed the highest growth rate in the dry season. The variety CT-608 showed a promising performance in the yield of total biomass and leaves, and CT-604 and CT-606 underwent a strong decrease. Only CF and digestibility in leaves and stems varied with the variety; while CP and Ca varied with the season, favorable for the rainy season. CT-604 and CT-606 had a better performance in CF and DM digestibility. With the results of both stages a multivariate analysis was made to determine the variables that influenced the agronomic performance and the relative contribution to the typification of the varieties. The variables of higher contribution to total variability in both seasons of the year were yield, absolute growth rate and leaf area. The typification of varieties in both seasons discards CT-606, CT-604 and CT-602 due to their low biomass productions. The introduction of varieties CT-600, 601, 603, 605, 607, 608 and 609 in the commercial areas of biomass production is recommended.