AGRONOMIC PERFORMANCE OF RELATED DURUM-WHEAT (TRITICUM-TURGIDUM L.) STOCKS POSSESSING THE CHROMOSOME SUBSTITUTION T1BL.1RS

Comparisons of bread wheat (Triticum aestivum L.) germplasms provided evidence that the T1BL.1RS chromosome substitution enhances agronomic performance and, particularly, grain yield, There are no known reports of the effect of this translocation in durum wheat (Triticum turgidum L.), however. The objective of this study was to determine the effect of the T1BL.1RS chromosome on gain yield, yield components, and other agronomic traits using 22 related durum lines (11 homozygous for chro mosome 1B, and 11 homozygous for T1BL.1RS). The test lines were produc ed by substituting the T1BL.1RS chromosome in T. turgidum cultivar Alt ar 84 (1B, 1B) through backcrossing, Two field trials were evaluated u nder optimum (five irrigations) and reduced (one irrigation) moisture conditions at the Mexican National Institute of Forestry, Agriculture and Livestock, Campo Agricola Experimental Valle del Yaqui (CAEVY) Res earch Center, Sonora, Mexico, during the 1993-1994 and 1994-1995 crop production cycles. The results indicated that the T1BL.1RS genotypes h ave increased above-ground biomass at maturity, increased 1000-kernel weight, and increased test weight in both irrigation treatments. The T 1BL.1RS lines also possessed longer spikes and headed and matured late r, The 1B lines produced more kernels m(-2) than the T1BL.1RS lines in all tests, however. The yield superiority and longer grainfilling per iod of the T1BL.1RS translocation group were detected only under reduc ed irrigation conditions. The average effect of T1BL.1RS across years and irrigation treatments was to increase grain yield and aerial bioma ss by 3.5 and 3.3%, respectively. The yield advantage was attributed t o increased kernel weight, test weight, and spike length.