Genealogia e base genetica dos cultivares brasileiros de feijão-caupi ( Vigna unguiculata (L.) Walp.)

Abstract

The expansion of production areas and consumer market of cowpea (Vigna unguiculata (L.) Walp.) has led to new demands on the objectives of genetic improvement of the crop. In this context, the knowledge of the status of the genetic base of this crop is of fundamental importance for the management and conservation of this genetic resource. The objective of this work is to estimate the genetic base of the cowpea cultivars recommended and released in Brazil between the years 1960 and 2020, to identify the ancestors of each cultivar, as well as to identify the origin of their cytoplasmic genes. To obtain this information, the pedigrees of the cultivars were elaborated. Forty-five cowpea cultivars were found to come from the crossing between 81 genotypes. Regarding the relative genetic contribution of the ancestors, it was observed that Pitiúba has contributed with 3.01% for the formation of cultivars, followed by Seridó and CNC 0434 each contributing with 2.81% and 2.78%, respectively. Next are Guariba, Vita 3 and Sempre Verde contributing 2.11% each, and Tvu 410 contributing 2.06%. Together, these contribute 16.98% of the total gene pool of the cultivars. Still worth mentioning are 19 ancestors that participated with 37% of the genetic base of the 45 cultivars. Regarding the origin of the cytoplasmic genes, of the 81 ancestors used in the crossings of cultivars, 38 were used as female genitors. Being the ancestors Pitiúba, CNC 0434, Seridó, IT85F-2687 and BR10 Piauí, the most significant cytoplasmic ancestral sources. Based on the data obtained, we have that the genetic base of the cowpea bean is relatively narrow.