Resumen

LOPEZ-HERNANDEZ, Mónica B. et al. Grain yield and its components, and root density in rice under irrigation and rainfed conditions. Agrociencia [online]. 2018, vol.52, n.4, pp.563-580. ISSN 2521-9766.

In Mexico, rice (Oryza sativa L.) is cultivated under irrigation and rainfed conditions with moisture restrictions and frequent periods of drought during the growing season. Grain yield (GY) is reduced severely when drought coincides with flowering and the grain-filling period. The objective of this study was to evaluate the GY and its components, and the root density (RD) in eight F6 lines of rice and one control (the national variety El Silverio), under irrigation (I) and rainfed (R) conditions in Zacatepec, Morelos, Mexico. The lines come from the nurseries of the Latin American Fund for Irrigation Rice (FLAR, for its acronym in Spanish; Santa Rosa, Cali, Colombia). The experiment was sown on June 10, 2013, with a seeding rate of 100 kg ha-1 and a fertilization rate of 180-40-40 of N-P-K. GY and the number of grains m-2 (G M-2) were the characteristics most affected by the water deficit in R. The RD in I (74 %) and R (72 %) was higher in the stratum of 0-30 cm; the RD in R (0.45, 0.26, 0.18 and 0.10 cm cm-3) was higher than in I (0.26, 0.16, 0.10 and 0.05 cm cm-3) in every stratum of the soil. Lines 2 and 7 were the most productive in I and R, and showed high aerial biomass (BM), harvest index (HI) and G M-2. Line 2; in addition, showed higher RD than the other lines in the strata of 15-30, 30-50 and 50-70 cm in I and R. The control showed lower GY and its components, and RD than the other genotypes. GY was positively related to its components in average of I and R. The most productive lines could be used commercially and as parents in a rice breeding program for irrigation and rainfed areas.

Palabras llave : aerial biomass; root density; water deficit; harvest index; genotype x environment interaction; grain yield.

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