Effect of establishment method on field performance of Stylosanthes guianensis lines

Abstract

Forage genotypes are often tested in evaluation trials established with transplanted seedlings or cuttings, whereas commercial pastures are usually direct seeded. Eleven Stylosanthes guianensis accessions were established by direct seeding (DS), transplanted seedlings (TS), or transplanted rooted stem cuttings (RC) in a space-planted field experiment to determine the effect of establishment method (EM) and particularly the magnitude of the genotype-establishment method (G-EM) interaction for dry matter forage yield, plant height and radius, and flowering abundance. Data were taken on 12 harvest dates covering 1 18 weeks from field planting. The large initial EM differences for yield (60.9, 99.4, or 92.7 g/ plant for DS, TS, or RC, respectively, at first harvest) diminished rapidly. The deviation of DS mean yield from the experiment mean increased linearly from the second to the 12th harvest, while that of TS decreased. EM effect on plant size closely paralleled that of yield. Initial EM differences in flowering abundance (RC > TS > DS) disappeared by 42 weeks from planting. While a significant G-EM effect was detected at some harvest dates, this was invariably much smaller than genotype or EM effects and did not materially affect genotype ranking. At 138 weeks following field planting, diameter of the largest root below 7 cm depth was greatest for DS while RC had the greatest number of roots. Agronomic evaluation of S. guianensis genotypes should not be greatly affected by EM when a common EM is used for all genotypes and when plants are allowed to establish well in the field before evaluation commences.