AGRONOMIC EFFICIENCY AND GRAIN QUALITY OF UPLAND RICE CULTIVARS AS A FUNCTION OF NITROGEN TOPDRESSING

This study aimed to evaluate the agronomic efficiency and grain quality of rice cultivars as a function of nitrogen application in upland conditions with supplemental sprinkler irrigation. The experiment was carried out in 2012/13 at Jaboticabal-SP on a randomized block and split plots design with four replications. The plots were composed of twelve rice cultivars (BRS Aroma, BRS Monarca, BRS Primavera, BRS Sertaneja, BRSMG Curinga, Caiapo, CIRAD 141, Guarani, IAC 165, IAC 201, IAC 202, and IAC 25), and two levels of nitrogen application (0 and 100 kg of N ha(-1)) in topdress at the R1 stage (panicle differentiation) as subplots. The N application intensifies the degree of lodging, mainly at Caiapo, Guarani, IAC 165, IAC 201 and IAC 25 cultivars. The N application affects the number of sterile spikelets per panicle, mainly in CIRAD 141, BRS Sertaneja, IAC 202, and BRS Aroma cultivars. Caiapo cultivar shows higher grain yield and agronomic efficiency in function of N application, followed by BRS Monarca, BRSMG Curinga, IAC 165, and IAC 202. Although Caiapo, CIRAD 141, Guarani, IAC 165, IAC 202, and IAC 25 cultivars present better results, all the others cultivars also present acceptable values of milling yield, without N application effects. The grain protein content in rice is increased by the N topdressing application.