Phenology associated with degree days for bean - cowpea cultivar BR-17 Gurguéia: A literature review

Cowpea ( Vigna unguiculata (L.) Walp.) is a culture that plays an important role in agricultural production of Brazilian states. While the culture is well researched, when referring to stages of development are little studies about. Therefore, the identification of phenological stages of crops is very important to facilitate the adoption of best management strategies to better yields and profitability. The objective of this review describe the phenological stages of cowpea cv. BR 17 - Gurgueia relating the number of degree-days (GDD) for each stage of development, indicating pests and diseases that can affect the crop. The phenology of plants has the remarkable characteristic the fact that the GDD is independent of the time and the planting site. Research has shown a greater adaptation of the cycle of some crops to GDD than the number of calendar days, and can estimate more easily cycle time, as well as establish the planting season due to the most appropriate time to harvest. The cultivar BR-17 Gurgueia has at least nine vegetative and reproductive stages having the lowest cumulative thermal demand stage V1 and reproductive stages require a greater number of degree-days compared to vegetative.