SALINITY EFFECTS ON VEGETATIVE GROWTH, SEED YIELD, AND FATTY-ACID COMPOSITION OF CRAMBE

Agronomic development and crop diversification may promote an increased acreage of crambe (Crambe abyssinica Hochst. ex R.E. Fries) in the USA. To determine whether crambe can be grown successfully on saline soils, a 2-yr-field-plot study was conducted. Five cultivars and three germplasm releases were grown with four salinity treatments imposed on a Pachappa fine sandy loam (mixed, thermic, Mollic Haploxeralf). Electrical conductivities of the irrigation waters, containing NaCl and CaCl2 (1:1 by weight), were 0.9, 3.7, 5.4, and 7.9 dS m-1. Seed yield, vegetative growth, and fatty acid composition of the seed oil were measured. Seed yield showed no statistical reduction over the salinity range tested each harvest year. Differences between harvest years were statistically significant. Analysis of the combined 2-yr data showed a 6.5% reduction of the combined 2-yr data showed a 6.5% reduction of seed yield for each unit increase in soil salinity above 2.0 dS m-1. These results place crambe in the moderately sensitive salt tolerance category. Individual seed weight was significantly reduced by salinity for six of the eight cultivars or germplasms studied. Increased salinity did not significantly affect the erucic acid component of the seed oil, but did significantly reduce the oleic, linolenic, and eicosenoic components.