Crude protein content in pigeon pea grain lines.

Pigeon pea (Cajanus cajan(L.) Millspaugh) is a multipurpose legume, which can be used as a grain producer, fodder and soil improver. Its nutritional composition has high protein, on average 22%, characterizing a relevant species in several emerging countries. Although it is an important crop in semi-arid regions of other countries, in Brazil has been little used and studied, so that it is still considered a subsistence culture. The goal of the present study was to evaluate the protein content in 21 lines of pigeon pea, from the breeding program of Embrapa Semiárido, including the control variety ‘guandu Petrolina’. The experiments were conducted in Barbalha/CE, Petrolina/PE and Juazeiro/BA, years of 2019, 2020 and 2021, distributed in four environments, three under irrigated cultivation and one under rainfed cultivation. The experiments were arranged in plots with two planting lines measuring 2.4m x 2.5m, spaced between rows by 1.2m and between plants by 0.5m, with twoplants per hole, using a randomized block design with three replications. The cultural treatments consisted of manual weeding, without any type of fertilization in the experimental area. The determination of total nitrogen and crude protein was performed using the Kjeldahl method. The genotype × environment interaction was highly significant (p<0.01) for protein content. There was no significant difference between the levels of protein under irrigated and rainfed cultivation. After joint analysis of variance among the four environments, the control cultivar 'Petrolina presented the highest average, with 24.60%. The lowest protein average was presented by treatment 17 (ICPL 900053 x Anagé), 20.12%. Lines 12 (ICPL 90053 x D2 Type), 9 (ICPL 90045 x ICPL 89027)and 19 (ICPL 89027 x D3 Type) expressed acceptable values for protein content, 22.35, 21.99 and 22.72%, respectively, associated with high productivity, broad adaptability and good predictability, showing great potential to be new cultivars to the Brazilian semiarid region.