Flowering Synchronization in Hybrid Rice Parental Lines at Different Sowing Dates

Mahmoud Gaballah,Hesham Alharby,Sharif Ahmed,Ayman El Sabagh,Ismail A Ismail,Hassan Hamad,Atif Bamagoos,Md Sohidul Islam

doi:10.3390/su13063229

Abstract

Hybrid seed set on the female line depends primarily on its flowering synchronization with the restorer line (R), therefore, the sowing of male and female lines must be planned properly to achieve this. Field experiments on different sowing dates (May 1st, May 15th, and May 30th) of R lines (Giza 178R, Giza 179R, and Giza 181R) and cytoplasmic male sterile (CMS) lines (IR69625A, IR70368A, IR58025A, K17A, and G46A) were carried out at the farm of Sakha Agricultural Research Station, Kafr El-Sheikh, Egypt during 2019 and 2020 to study the effect of sowing dates on flowering synchronization in hybrid rice. The results indicated that the synchronization of flowering between CMS lines and R lines has highly significant effects on the days to 50% heading, number of leaves, effective accumulated temperature (EAT), plant height, panicle exertion percentage, panicle length, number of fertile panicles, panicle weight, seed set percentage, harvest index and seed yield of hybrid rice. The highest seed yield (1.72 and 1.41 t ha−1, respectively in 2019 and 2020) was recorded from the sowing date May 1st and the hybrid combination of Giza 178R × IR58025A (2.06 and 2.12 t ha−1 in 2019 and 2020, respectively). The grain yield had a significant and highly significant positive correlation with the plant height (cm), panicle exertion percentage, panicle length, number of panicles plant−1, panicle weight, seed set percentage, and harvest index. In Egypt, May 1st is the best time for the synchronization of hybrid rice lines and a combination of Giza 178R × IR58025A may be recommended for better performance.

Highlights

Rice is an important food crop and the main food source for more than half of the global population
The ordinary analysis of variance results indicated in both years highly significant differences among sowing dates (S) for all traits studied in both years (Table 3)
There was a significant effect of sowing dates on different traits (Table 4)

Summary

Introduction

Rice is an important food crop and the main food source for more than half of the global population. Rice is cultivated in Egypt over an area of about 660 thousand hectares, with an annual production of about 4.6 million tons of paddy, with average productivity of 10 tons per hectare [1]. Hybrid rice production is an innovative technology to increase further rice productivity, leading to food security and the reduction of poverty in Egypt. This technology can be used to increase the current yield in rice, where the yield levels of the conventional cultivars have stabilized and reported yield advantage of 15–20%. The heterosis advantage of hybrids may be expressed by superiority over inbred varieties in vigor, number of productive tillers, panicle size, number of spikelets/panicle, and grain yield. The heterosis advantage of hybrids may be expressed by superiority over inbred varieties in vigor, number of productive tillers, panicle size, number of spikelets/panicle, and grain yield. 4.0/).

Methods

Results

Discussion

Conclusion