MULTIPLE-TRAIT SELECTION IN A RECURRENT SELECTION POPULATION IN OAT (AVENA-SATIVA L)

Single trait selection is often utilized to maximize genetic gain in r ecurrent selection systems. However, traits negatively correlated to t he primary trait can deteriorate with single trait selection. Multiple trait selection can be used to prevent or correct correlated trait de ficiencies. Our objective was to compare the effectiveness of several multiple trait selection schemes with selection for grain yield alone. Five multiple-trait selection schemes were evaluated for their effect on total genotypic worth and individual trait responses in an ''opene d'' oat (Avena sativa L.) recurrent selection population. Grain yield, days-to-heading, plant height, and reaction to barley yellow dwarf vi rus (BYD) were studied in several environments, The phenotypic correla tions with yield were 0.44 and 0.60 for heading date and plant height, respectively. There was no association between yield and BYD, A restr icted index, a Smith index, a modified base index, a multiplicative in dex, and independent culling were evaluated and compared with selectio n for yield alone, The restricted and Smith selection indices, when co mpared with selection for yield alone, selected genotypes with improve d heading date, plant height, and BYD with only negligible decreases i n yield, Greater correction for heading date and plant height was achi eved with the modified base index, the multiplicative index and indepe ndent culling, but yield decreased accordingly, Realized gains in tota l worth for the restricted index were 15% above, and the Smith index 1 4% above, the gain realized by selection for yield alone. Restricted a nd Smith index selection were effective at preventing secondary traits from deteriorating through selection for grain yield.