Screening bean cultivars in relation to higher efficiency of phosphorus use

Abstract

Screening of bean (Phaseolus vulgaris L.) cultivars of phosphorus efficiency was carried out in three stages: 1) determination of recommendable doses of phosphorus; 2) screening large number of cultivars and 3) verification of validity of the screening methodology. Results obtained in the first experiment in Yellow Red Latosol pointed out 30 and 120 kg/ha P₂O₅/ha as low and high recommendable doses of phosphorus, respectively. After establishing the recommendable doses, two hundred eighty nine bean cultivars were evaluated in rows five meters long. Based on yield and phosphorus use efficiency parameters (α), cultivars were classified into four groups: responsive and efficient (RE), non responsive but efficient (NRE), responsive but inefficient (RIE) and no responsive and inefficient (NRIE). Experimental results showed that 80% of the cultivars tested fall under the same group as they were classified in the screening of cultivars. Those cultivars presenting higher grain yield/kg P₂O₅ ratio than the mean ratio obtained in low level of phosphorus were named efficient cultivars (E) and those cultivars responding to adequate phosphorus levels were named responsive cultivars (R). The most efficient cultivars under low level of phosphorus were: CNF 0168, CNF 0174, CNF 1139, CNF 0173 and CNF 0117.