Search

Systematic performance trials have been conducted in several states for more than 20 yr to evaluate agronomic performance of annual rye- grass (Lolium multiflorum Lam.). Despite development and testing of many annual ryegrass cultivars, the first improved cultivar, Gulf, has remained one of 10 to 12 cultivars recommended for planting in the southeastern USA. Our objectives were to evaluate cultivar yield performance across 12 yr at five locations, to assess cultivar yield distribution within growing seasons, and to estimate cultivar yield stability (consistency of relative performance environments). Efficacy measures were early-season yield (total before 1 March), late-season yield (total after 1 March), and total annual yield. Overall means for all cultivars and individual cultivar performance (for common years) were compared with Gulf or Marshall. Neither location effects nor cultivar × location interactions were found. Cultivar and year effects, plus cultivar × year interactions were detected (P < 0.05) for all three yield responses. Mean early season yields ranged from 2.3 to 4.6 Mg ha-1, with mean late-season yields ranging from 5.1 to 7.4 Mg ha-1. No trend existed for mean total yield relative to Gulf or Marshall to increase over time in association with availability of newer cultivars. Given large yearly fluctuation in yields, it is apparent that unpredictable environmental factors, including climate and perhaps pests, are the primary determinants of annual ryegrass performance rather than differences in yield potential among cultivars. Thus, yield stability may be an appropriate selection factor to include among the criteria for development of improved annual ryegrass cultivars. [ABSTRACT FROM AUTHOR]

Abstract Annual ryegrass (Lolium multiflorum Lam.) is grown on more than one million ha in the south-eastern USA each year. Recommended and actual seeding rates vary substantially within the region. The objective of this study was to evaluate variation in seed weight, germination, seedling vigour and seasonal yield performance among annual ryegrass cultivars. During 1997, 1998 and 1999, seed from fourteen commercial cultivars was weighed and germinated to determine numbers of pure live seed (PLS) m-2 before yield evaluation at four locations. Seed from ten cultivars was planted at 0·7 and 2·0 cm depth in a greenhouse study to evaluate relative seedling vigour. Cultivar mean single-seed weight ranged from 2·4 to 4·8 mg in 1997, 1·8 to 4·5 mg in 1998, and 2·6 to 4·6 mg in 1999. Seed germination ranged from 78·8% to 98·0% in 1997, 82·3 to 98·3% in 1998 and 77·8 to 98·3% in 1999. Seed number, PLS m-2 , ranged from 675 to 1289 in 1997, 710 to 1550 in 1998, and 717 to 1179 in 1999. Among the ten cultivars evaluated for seedling vigour, seedling weight differed between planting depths and a significant cultivar by year interaction was observed. Seedling weight was highly correlated with seed weight at each seeding depth. The effect of increasing number of PLS m-2 on subsequent yield performance, although small, was consistently negative. These results indicate that target plant populations may be obtained more economically by adjusting seeding rates for seed size differences among cultivars and seed lots of annual ryegrass. [ABSTRACT FROM AUTHOR]

Features the U.S. registration of the cultivar 'Shiwasuaoba' annual ryegrass, Lolium multiflorum. Research leading to the development of Shiwasuaoba; Developers of the cultivar; Breeding program; Resistance to crown crust; Possession of several B-chromosomes.

Offers information on the registration of the cultivar Secretariat Kentucky ryegrass with the agricultrual authorities in Washington. Developer of the plant variety; Plant structure and appearance; Average annual seed yield.

Reports on the registration of the cultivar Jumbo tetraploid annual ryegrass, with the U.S. Department of Agriculture. Origins of the cultivar; Development of the breed; Average grain yield.