The domestication of the native grasses Danthonia richardsonii Cashmore and Danthonia linkii Kunth for agricultural use. I. Selecting for inflorescence seed yield

摘要

Ecotypes of the native grasses Danthonia richardsonii Cashmore and Danthonia linkii Kunth (wallaby grasses) were collected, mostly in northern New South Wales, in 1985-86. All the D. richardsonii plants were 2n = 48 and all the D. linkii plants were 2n = 24. These were grown as spaced plants (1 x l m grid) in a parent nursery at the Agricultural Research Centre, Tamworth, and assessed for seed yield per inflorescence and traits related to seed retention within and between four successive generations. The aim of the study was to identify individual seed retaining plants over these generations. Selection of individual plants within generations was based mainly on seed yield per inflorescence as well as inflorescence shape as an indicator of seed retention. From approximately 1750 parent plants, 144 D. richardsonii and 19 D. linkii accessions remained in the fourth generation selections. Of these seven D. richardsonii and three D. linkii plants were identified as having high inflorescence seed yield. Over the four ge nerations, mean inflorescence seed yield (g per five inflorescences) increased from 0.31 to 0.42 g for D. richardsonii and from 0.12 to 0.39 g for D. linkii. Mean seed yields for selected lines in the fourth generation were 0.80 g for the seven D. richardsonii selections and 0.59 g for the three D. linkii plants. Selection resulted in an increase in glume width and the number of days to first flower in both species. Mean inflorescence length and width varied little over the four generations. Between successive generations (parent, G2, G3 and G4) 10, 5 and 6 D. linkii plants had inflorescence seed yields higher than the mean, compared with 42, 46 and 35 G4 D. richardsonii plants. However, only 17 of the D. richardsonii and three of the D. linkii plants had inflorescence seed yields greater than the mean in all generations. Autumn inflorescence seed yields in the third and fourth generations were also used as additional selection criteria for selecting seven D. richardsonii plants for further evaluation and possible commercial release.