Evaluation of bred lines of Macroptilium atropurpureum

Abstract

Improvement over cv. Siratro in five advanced lines from an M. atropurpureum breeding programme was evaluated at four sites (with two soil-types at one site) during four growing seasons. On all except four of the 20 environment/season occasions all the bred lines produced a dry-matter yield markedly higher than that of Siratro. However, this increase in vegetative vigour was obtained at the expense of some reduction of viable seed addition to the soil, although it was considered that, at least under the conditions of the experiment, sufficient seed of all lines was added to soil for their persistence in pastures. Two of the lines (18 and 19) were extremely versatile, with a good performance at all sites; the others (2, 13 and 15) showed some small degree of differential environmental tolerance. It was concluded that the two most specialized environments (Beerwah and Narayen brigalow) could have been excluded from the experiment without diminishing the results. If only relative line performance had been required, a single season would have sufficed; but for a realistic estimate of yield all four seasons (one unusually wet, one unusually dry and two average) were essential. It is recommended that in future work more attention should be paid to standardizing management procedures over all sites.