Breeding oat for aluminum tolerance

Abstract

Aluminum toxicity is a growth-limiting factor for crop production in the south brazilian soils. This toxicity can be avoided by raising pH up to 5,5 - 6,0 with aglime or by growing Al tolerant cultivars. A oat breeding program for aluminum tolerance has been carried out since 1986 at the University of Passo Fundo by using segregating populations from F2 to F5, at acid soils, on field conditions (Floss et al., 1991). Floss et al. (1993) reported results about a screening for Al tolerance where 156 genotypes of oats (Avena sativa L.) were grow in nutrient solutions (growth chamber). On of the most Al tolerant genotype obtained in thi screening was the cultivar Steele, from USA. In field conditions and acidic soils, many tolerant lines were selected and evaluated for other important traits, as grain yield, test weight, disease resistance, plant height, days from emergency to flowering and to maturity, and grain quality. One line from this segregating populations, line UPF92Al300, introducted in 1992 by Quaker Oat Nursery (cross QR=981=UPF80197/(X2082- 2/CI8428)/Steele, made in College Station by Milton McDaniel, was selected as aluminum tolerant and evaluated in test trials from 1998 to 2001. This line was released in 2002, by the University of Passo Fundo (UPF), named UPFA 20-Teixeirinha. The average performance obtained at 14 different fields, from 1998 to 2002 was: yield = 3049 kg ha-1; test weight = 50 kg hL-1; thousand grain weight = 36 g; days to heading =87; days to maturity=131; height =103 cm; % of grains wider than 2mm =84; % of groats =71; and moderate resistance to leaf and stem rust. Floss,E.L. et al. Primer congreso sudamericano de avena, Tres Arroyos/ Argentina, 1991, Resumos. p.15; Floss, E.L. et al. In:V International Oat Conference, 1996. Proceedings. Saskatoon, 1996,p. 623-625.