Field Performance of Select Tepary Bean Germplasm in the Tropics

Abstract

Dry edible bean (Phaseolus vulgaris L.), a staple food crop for many tropical countries, is not well adapted to the hot temperatures and low rainfall that prevail during the dry seasons. Cultivated tepary bean (Phaseolus acutifolius A. Gray var. latifolius Freeman), an edible small‐seeded desert annual with extreme tolerance to drought, may be suited to dry‐season production in the tropics. To test this hypothesis, production potential of select cultivated tepary bean germplasm was evaluated in different tropical environments and compared to dry bean. Eleven lines (Neb‐T‐l‐s, Neb‐T‐6‐s, Neb‐T‐Sa‐s, Neb‐T‐15‐s, GN‐605‐s, GN‐610‐s, Pls 321637‐s, 321638‐s, 440788‐s, 440806‐s, and 502217‐s) were field tested from 1989 to 1993 in six trials, two each at Isabela and Fortuna, Puerto Rico, and El Zamorano, Honduras. Locally adapted, high‐yielding dry bean checks included in some trials in Puerto Rico were ‘Dorado’ and ‘Arroyo Loro’. Tepary lines yielded 70% of Dorado in the warm environment of lsabela and 170% of Dorado and Arroyo Loro in the hot environment of Fortuna. Tepary seed weight averaged 30% less than the dry bean cheeks. Seed protein concentration of tepary bean averaged 12% less than Dorado, and the seed protein concentration was inversely related to yield (r − 0.70*). Tepary bean proanthocyanidin (condensed tannin) concentration, an antinutritional factor, was 73% less than Dorado. The tepary bean lines have potential for dry‐season production in the tropics where dry bean traditionally yields poorly.