Performance of F1 Hybrids from Crosses of Three Sudangrasses and Six Forage Sorghums with A Rhodesian Sudangrass

Abstract

A cytoplasmic male-sterile sudangrass (A Rhodesian) was crossed with three other sudangrasses (Common, Greenleaf, and Piper) and six forage sorghums (Sart, Millo Blanco, Bloomless, Forage Sorgo x Sugar Drip, Collier, and Brawley). The nine F₁ hybrids were compared for yield of green forage (GF), yield of dry forage (DF), crude protein (CP) content, CP yield, and height at lsabela, Puerto Rico. Four cuttings were made. The first was 45 days after planting and the remaining three were at about 30-day intervals thereafter. The second harvest had the highest DF yield but the lowest CP content. The CP content was 15.7, 12.2, 14.6, and 15.6% for harvests 1, 2, 3, and 4, respectively. When data for all four harvests were combined, the F₁ hybrid of A Rhodesian sudangrass x Common produced the highest GF ana DF yields, 143 kg•ha^-1•day^-1 of the latter which was 30% and 29% more than the 2nd and 3rd- highest DF producing hybrids. Differences in CP content among the nine F₁hybrids were not significant, but A Rhodesian sudangrass x Common produced the highest CP yields. The tallest F₁ hybrids were A Rhodesian x Common and A Rhodesian x Greenleaf. The GF and DF yields of A Rhodesian x Common were excellent. The results indicated that A Rhodesian sudangrass is a male-sterile line with potential for use in the development of superior F₁ forage-sorghum hybrids in Puerto Rico.