SEEDLING VIGOR OF SOME LEUCAENA SPP AND THEIR HYBRIDS

The seedling vigour of 19 leucaena lines comprising principally the sp ecies Leucaena leucocephala, L. pallida, L. diversifolia and their hyb rids was studied in glasshouse and field experiments in Hawaii between April and July 1991. Seedling vigour assessment was based on plant he ights and plant weights during 84 days of growth. L. pallida and its h ybrids with L. leucocephala gave more than twice the early growth of L . leucocephala cv. Cunningham or the common, weedy Hawaiian type, whic h were not significantly different. The early growth of the arboreal l ine, L. leucocephala K636, was greater than that of Cunningham, and it s hybrids with L. pallida were outstanding. In the first 6 weeks of gr owth, L. diversifolia genotypes were less vigorous than L. pallida and , with the exception of CP146568, were less vigorous than Cunningham. Days to emergence and growth at 16 days in the glasshouse were good in dicators of subsequent growth potential both in the glasshouse and in the field. The implications of the results for breeding psyllid-resist ant leucaena are discussed.