Breeding SCN-resistant soybean lines with improved oil and protein contents

Soybean cyst nematode (SCN) disease caused by <i>Heterodera glycines</i> is one of the most devastating diseases in soybean (<i>Glycine max</i> L.) and results in significant yield losses annually worldwide. Breeding crops for resistance is an eco-friendly approach to minimize these losses. In this study, SCN-resistant germplasm with excellent agronomic traits was obtained through cross-breeding between resistant germplasm sources and local cultivars that were high-yielding but susceptible to SCN in China's two major soybean-growing regions. Using the single seed descent method, plants with favorable agronomic traits were selected and then planted into rows to raise seeds for marker assays and environmental-controlled bioassays. Finally, three lines from Northeast China and three from the Huang-Huai Valleys, all harboring resistance to races 1, 3, and 5, were selected. Their 100-seed weight ranged from 18.91 g to 21.6 g. The average oil contents of the three high-oil-content lines (QingF6-67, QingF6-98, and QingF6-99) from Northeast China ranged from 19.96% to 22.74%. The average protein contents of the three lines (HHF7-3-10, HHF7-6-6, and HHF7-6-10) from the Huang-Huai Valleys ranged from 42.3% to 43.5%. These six resistant lines, which have increased seed oil or protein contents, could be used as resistant cultivars against SCN or advanced donor parents in soybean breeding programs.