TILLERING PATTERNS OF SPRING WHEAT GENOTYPES GROWN IN A SEMIARID ENVIRONMENT

Abstract

Replicated field trials were conducted for 2 yr at two locations in a semiarid short-season environment to compare the tillering patterns of three spring wheat genotypes. Neepawa (high tillering), Siete Cerros (low tillering) and M1417 (oligoculm) were evaluated at five seeding rates (40–640 seeds m−2). Genotypes, locations, years, and seeding rates had significant effects on tiller appearance rate (TAR), maximum tiller number (TMAX), days to TMAX (DTMAX), tiller senescence rate (TSR), tiller mortality (TM) and number of spikes (SN). Genotype × seeding rate and/or year × genotype interactions were detected for TAR, TMAX, TSR, TM and SN. For Siete Cerros, TAR and TSR were constant proportions of those for Neepawa over the four lowest seeding rates. In contrast, TAR and TSR for M1417 increased in proportion to those for Neepawa with increased seeding rate. Similar relationships were observed for TMAX and SN in 1984, but not in 1985. Siete Cerros had higher TM than Neepawa and M1417, especially at low seeding rates. Changes in genotype rank from one seeding rate to another were observed for TAR, TMAX, TSR, and TM, but not for SN. Changes in rank suggest that different tillering patterns may be better suited to different growing environments.Key words: Wheat (spring), tillering patterns, seeding rates