Agronomic performance and forage quality of S4 corn lines in topcrosses with single cross hybrid

Abstract

The objective of this study was to evaluate the relative performance of 74 partially inbred lines (S4) from crosses between the commercial hybrids P30P70 and Dow8460 in topcrosses with the commercial single cross hybrid P30F53 (tester), and checks (hybrids Dow8460, P30F53 and Status). The grain yield (GY) was evaluated in two environments in Guarapuava-PR. The effects of genotypes, environments and genotypes x environments interaction were significant for grain yield (GY). Among the topcrosses hybrids (TCH) the GY ranged from 8,302 (TCH 123, in the environment 2) to 14,809 kg ha-1 (TCH 11, in the environment 1). In the environment 1 we evaluated agronomic characteristics of the forage and bromatologic characteristics of the silage. The green mass productivity (GMP) of forage ranged from 49,857 (TCH 208) to 80,642 kg ha-1 (TCH 22) and the dry mass productivity (DMP) ranged from 11,072 (TCH 217) to 24,143 kg ha-1 (TCH 22). The contents of neutral detergent fiber (NDF) ranged from 45.39 (TCH 80) to 56.71% (TCH 77) and the contents of acid detergent fiber (ADF) ranged from 25.45 (TCH 80) to 35 60% (TCH 99). The relative value of the silage (RVS) presented average ratios ranged from 103 (TCH 148) to 142 (TCH 80). For all the characteristics many topcrosses did not differ from the best checks. TCH 22 and 53 were higher considering the set of all characteristics of forage and silage and, also, it showed high grain yield, therefore, these inbred lines should be advanced in the breeding program.

Keywords

• Zea mays; Partially inbred lines; Topcross; Plant breeding.