Avaliação de linhagens de trigo originárias de hibridação com e sem irradiação gama

The mutation induction technique associated with hybridization has provided the development of new genotypes with desirable agronomic traits. Seeds of eighteen F2 wheat lines being ten originated by plant selections of the Kauz "S" x IAC-24 hybrid, were irradiated (I) with gamma rays and eight non irradiated (NI) plus the check cultivars IAC-24 and IAC-289 were evaluated for grain yield, agronomic characteristics and disease resistance in six trials carried out at different locations, under sprinkler irrigation (limed soils) and dryland (limed and acid soils) conditions, during 1997-99. In laboratory conditions, the genotypes were evaluated for their toxicity tolerance in nutrient solutions using as controls the cultivars BH-1146 (tolerant) and Anahuac (sensitive). The line L18-I was superior for grain yield under limed soil and sprinkler irrigation conditions. Under dryland and acid soil, the line L20-I, tolerant to Al3+toxicity in nutrient solutions, presented good grain yield differing only from IAC-289, the most sensitive to Al3+ toxicity. IAC-289 and line L9-NI had good performance under limed soil and dryland conditions. L11-I exhibited the shortest plants in all trials, to lodging resistance and tolerance to Al3+ toxicity. All genotypes were susceptible to leaf spot. L9-NI had good potential as source of resistance to leaf rust. Except to Anahuac, IAC-289 and line L3-NI, all genotypes were tolerant to the presence of 10 mg L-1 of Al3+, in nutrient solutions.