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Differential partitioning of photosynthate has been suggested as the reason for low early-season (8 to 12 wk post planting) dry matter (DM) yield of 'Savanna' stylo [Stylosanthes guianensis (Aubl.) Sw.], a facultative annual over much of its Florida range. In a 3-yr field study (1991-1993), the effect of planting date (April vs. June) on root-to-shoot ratio (g g -1 ), leaf-to-stem ratio (g g -1 ), and total plant weight (g) of Savanna stylo was compared with common alyceclover [Alysicalpas vaginalis (L.) DC.], a true annual, for 16 wk post planting. Only time post planting consistently affected root-to-shoot ratio, which declined as time post planting increased. Within years, leaf-to-stem ratio also declined with increasing time post planting, but, on average, Savanna stylo had a higher leaf-to-stem ratio than alyceclover. There was a planting date x legume x year x time post planting interaction for total plant weight. This was because total plant weights, although similar regardless of planting date or legume in 1991 and 1993, differed in 1992, when April-planted Savanna stylo plants had greater total plant DM than June-planted Savanna stylo or either planting date of alyceclover. Across the 16-wk post-planting period, there was a consistent legume x planting date interaction each year for total plant weight. This was because both April-planted legumes were vegetative for the full 16-wk post-planting period (April-August) and total plant weight remained similar, but only Savanna stylo remained vegetative for the full 16-wk post June-planting period (June-October). Total plant weight of June-planted alyceclover was lower due to flowering and leaf loss in the later part of the 16-wk post-planting period. These data indicate that the lower early-season DM yield of Savanna stylo compared with alyceclover is not due to physiological differences associated with perennial and annual growth habits.

Most tropical grasses are nutritionally inadequate during the fall to support weight gains in replacement heifers. The objective of this study was to determine how the newly developed, perennial tropical legume, 'Savanna' stylo [Stylosanthes guianensis (Aubl.) Sw.] PI 562697, when grown as an annual, would compare with the true annuals, alyceclover [Alysicarpus vaginalis (L.) DC] and hairy indigo (Indigofera hirsuta L.), as a stockpiled forage for the fall. Savanna, common alyceclover, and 'Flamingo' hairy indigo were planted in a replicated field trial in June 1989 and 1990. Growth rate (Ib/sq yd/d), dry matter (DM) yield, crude protein (CP), and in intro organic matter digestibility (IVOMD) were determined for each legume in August, September, October, and November of each year [...]

SONODA, R. M., and J. B. BROLMANN. 1980. Differences in susceptibility of Stylosanthes hamata to Colletotrichum gloeosporioides. Plant Disease 64:553-554. Anthracnose incited by Colletotrichum gloeosporioides was more severe on accessions of Stylosanthes hamata indigenous to the southeast coast of Florida with 2N=40 chromosomes than on those with 2N=20 chromosomes. The 2N=40 S. hamata were found in four localized areas and the 2N=20 ecotypes were widely distributed along the southeast coast of Florida. The 2N=40 accessions had a smaller beak on their seedpods and grew more vigorously in forage evaluation tests. Further tests are needed to determine whether the two types are conspecific. Stylosanthes hamata L. is indigenous to the southeast coast of Florida and to various areas in the Caribbean, Central America, and South America (7). It is one of several Stylosanthes spp. being tested as a forage plant in south Florida (2). One of the limiting factors in the use of Stylosanthes spp. is susceptibility to anthracnose incited by Colletotrichum gloeosporioides (Penz.) Sacc. (5). The C. gloeosporioides attacking Stylosanthes spp. in commercial and experimental plantings in Florida was probably introduced on contaminated seed (4). The pathogen was not found in surveys of native stands of S. hamata (10) along the southeast coast of Florida. Most of the S. hamata accessions collected from southeast Florida in the summer of 1979 were highly tolerant to C. gloeosporioides when inoculated (10). Three accessions were moderately susceptible (10). The most susceptible line was similar in pod morphology, ie, short beak, to an accession collected in 1971 that had excellent agronomic characteristics (2) but whose forage yield was reduced by C. gloeosporioides (6). The accession collected in 1971 had 2N=40 chromosomes, whereas most S. hamata accessions have 2N=20 chromosomes (3). A study was conducted to determine if differences in susceptibility of S. hamata indigenous to southeast Florida coincided with differences in chromosome number and pod morphology. MATERIALS AND METHODS Descriptions of S. hamata collected from native stands of the species from Fort Pierce, FL, south to Key West during the past 10 yr (approximately 200 collection sites) were searched for Florida Agricultural Experiment Stations Journal