Breeding of ZhongKeFaZaoGeng1 by molecular design.

Double-cropping early-season rice is one important part of staple crop rice. In recent years, great progress has been made in breeding the double-cropping early-season japonica rice variety, ZhongKeFaZaoGeng1 (ZKFZG1), with high yield, good quality, and high resistance. The breeding of ZKFZG1 aimed at the severe problems of low quality, low income and pre-harvest sprouting in double-cropping early-season rice production, and was achieved through molecular design by selecting three parents with different beneficial genes, KongYu131, NanFangChangLiGeng, and JiGeng88 and screening for key agronomic genes in cross-breeding. ZKFZG1 has a compact plant architecture, a plant height of ~90 cm, a number of ~120 grains per panicle, a setting rate of ~85%, a 1000-grain weight of 26 grams, a yield of 8.25 t/ha, and especially good grain quality. The successful breeding of ZKFZG1 provides a new direction for double-cropping early-season rice production.