Response of bean cultivars to sulphur

The present experiment was carried out under greenhouse conditions at the S oil Science Department of Universidade Federal de Lavras (UFLA), using a Da rk-Red Latosol (Oxisol), medium texture, cerrado phase, from Itumirim munic ipality, MG, Brazil. The objective of this research was to evaluate the eff ects of sulphur rates in the growth of different bean (Phaseolus vulgaris L .) cultivars, and to determine the critic levels of S in the shoots. The tr eatments consisted of four S rates (0, 30, 60 and 120 mg/kg soil) and three bean cultivars (Carioca, Ouro and H-4), arranged in a completely randomize d design, replicated three times. The cultivars showed significant response s in shoot dry matter (SDM) production when S was applied; however, the gai ns in SDM varied according to the cultivar. Except for the H-4 cultivar, th e S fertilization also increased the root dry matter production, but with t ower increases than that observed for the SDM. The N/S and P/S relations, a s well as the critic levels of S in the SDM, corresponding to 90% of the ma ximum SDM, varied among cultivars. The N/S relations in the SDM were 20.97, 20.81 and 18.68, whereas the P/S relations were 2.24, 1.33 and 0.87, respe ctively in the Carioca, Ouro and H-4 bean cultivars. The critic levels of S in the SDM were 1.89, 2.21 and 2.16 g of S/kg, for Carioca, Ouro and H-4 b ean cultivar, respectively. The S utilization efficiency at the S doses eno ugh to reach 90% of the maximum SDM varied according to the bean cultivars, showing that the selection and breeding of the genetic material adapted to different S soil availability is possible.