NuMex Sunlite is a bolting-resistant, pink root (Pyrenocheata terrestris) resistant, yellow grano-type onion (Allium cepa L.) developed for early fall planting. The release of NuMex BR1 as a bolting-resistant, yellow grano-type in 1981 had a significant impact on the New Mexico onion industry. Bolting resistance permits early planting and increases yield potential, and the greater plant development in cool season, resulting from early planting, helps control pink root losses, which are most severe in warm weather. More than one-half the New Mexico short-day crop in 1986 was NuMex BR1. NuMex Sunlite resembles NuMex BR1 in bolting resistance, plant characteristics, and yield potential. NuMex Sunlite has a higher level of pink root resistance than NuMex BR1 and is suggested for early fall planting on fields severely infested with P. terrestris.

NuMex Sunlite, like NuMex BR1, was developed by selection from Texas Early Grano 502 PRR. The first selection was among half-sibs from bulbs selected for bolting resistance. Progeny from selected half-sibs were recombined (intercrossed). Bolting-resistant bulbs from the recombination were selfed, and the progeny were screened in a field disease nursery for uniformly high levels of pink root resistance. Bulbs from resistant progeny were intercrossed to produce NuMex Sunlite.

Plant characteristics and maturity date are similar to Texas Grano 502 PRR. Bulbs are medium deep, top-shaped, with rounded shoulders and refined neck. NuMex Sunlite is distinguished by uniformly high levels of pink root resistance and bolting resistance similar to NuMex BR1. In controlled experiments on severely infested pink root fields, NuMex Sunlite has been more productive than NuMex BR1. On non-infested fields, yields of the two are similar. In commercial fields with severe pink root infestation, NuMex Sunlite maintained extensive root capacity until maturity and produced uniformly large bulbs. In contrast, NuMex BR1 had many susceptible plants with minimal root capacity, which produced small bulbs. Observations suggest, even on the most severely infested pink root fields, early NuMex Sunlite plantings will produce optimum yields. Bulbs of NuMex Sunlite, compared to NuMex BR1, are firmer and have a more rounded top and more refined neck. These characteristics should improve onion curing and handling qualities.