Productivity of Two Rice Varieties Using Ratoon System Through N Fertilizing Treatments at Two Flooding Types on Tidal Lowland Area

Aims: This research objective was to determine productivity of two rice varieties using ratoon system through regulation of N fertilizer application at two flooding types in tidal lowland area. Place and Duration of Study: The study was conducted from February to July 2020 at two locations in tidal lowland area, i.e. B-type flooding located at -203859, 132S 10404428,449E and C-type flooding located at -203858,81S 10404426,745E in Mura Sugih Village, Tanjung Lago Subdistrict, Banyuasin District, South Sumatra, Indonesia. Study Design: The experimental design used in this study was Factorial Randomized Block Design with two treatments factors and four replications. The variety treatments (V) were consisted of V1: Inpari 30 and V2: Hipa 5 Ceva. N fertilizer application treatments (A) were consisted of A1: N fertilizing: 1/3 dose at planting period + 1/3 dose at 42 dap + 1/3 dose at 1 day after harvest (dah) of main crop; A2: N fertilizing: 1/3 dose at planting period + 1/3 dose at 42 dap + 1/6 dose at 1 dah of main crop + 1/6 dose at 21 dah of main crop. Result: The results showed that N fertilizer application regulation can increase productivity of two rice varieties using ratoon system at two flooding types land in tidal lowland area. Productivity of rice hybrid (Hipa 5 ceva) tend to be higher than that of rice inbred (Inpari 30) using ratoon system at two flooding types land in tidal lowland area. Productivity of two rice varieties using ratoon system tend to be higher at B-flooding type land than that of C- flooding type land.

Contrasting yield formation characteristics in two super-rice hybrids that differ in growth duration

Summary The development of high-yielding, short-duration super-rice hybrids is important for ensuring food security in China where multiple cropping is widely practiced and large-scale farming has gradually emerged. In this study, field experiments were conducted over 3 years to identify the yield formation characteristics in the shorter-duration (∼120 days) super-rice hybrid ‘Guiliangyou 2’ (G2) by comparing it with the longer-duration (∼130 days) super-rice hybrid ‘Y-liangyou 1’ (Y1). The results showed that G2 had a shorter pre-heading growth duration and consequently a shorter total growth duration compared to Y1. Compared to Y1, G2 had lower total biomass production that resulted from lower daily solar radiation, apparent radiation use efficiency (RUE), crop growth rate (CGR), and biomass production during the pre-heading period, but the grain yield was not significantly lower than that of Y1 because it was compensated for by the higher harvest index that resulted from slower leaf senescence (i.e., slower decline in leaf area index during the post-heading period) and higher RUE, CGR, and biomass production during the post-heading period. Our findings suggest that it is feasible to reduce the dependence of yield formation on growth duration to a certain extent in rice by increasing the use efficiency of solar radiation through crop improvement and also highlight the need for a greater fundamental understanding of the physiological processes involved in the higher use efficiency of solar radiation in super-rice hybrids.

Comparison of the F2 and F3 traits’ inheritance by the rice hybrid ‘Kontro x Kuboyar’

Rice is a very moisture-loving crop, therefore it suffers greatly from drought. However, in the world in recent years, there is an increasing shortage of fresh water, which makes the use of upland rice relevant. Therefore, rice varieties with a reduced demand for water supply, developed as a result of breeding work, are more profitable for agricultural producers than agrotechnical or reclamation measures. It is much cheaper to produce such rice with periodic irrigation. The purpose of the current study was to analyze genetically the main quantitative traits of the rice hybrid ‘Kontro x Kuboyar’ with the selection of the best forms for subsequent breeding for drought resistance. The study was carried out in 2019–2020 on the rice plots of the special subdivision ‘Proletarskoye’ belonging to of the Agricultural Research Center “Donskoy” in the Rostov Region. In the course of the study there has been made a genetic analysis of a number of quantitative traits that determine rice productivity. The character of traits’ inheritance in the second and third generations was identical. The inheritance of the trait ‘panicle length’ was characterized by partial negative dominance and monogenic differences in parental varieties. The trait ‘number of spikelets per panicle’ was inherited according to the type of negative dominance of smaller values of the trait and was determined by the interaction of two pairs of genes. The trait ‘1000-kernel weight’ was identified by the partial dominance of large values of the trait and monogenic differences in the parental varieties. The traits ‘kernel length’ and ‘kernel width’ were split according to the monohybrid scheme 1:2:1, and there was no dominance. From the third generation, the best early-maturing forms with optimal values of the traits ‘plant height’, ‘panicle length’, ‘1000-kernel weight’ and ‘the best kernel percentage per panicle’ were selected for the subsequent breeding of drought-resistant rice varieties.