Inheritance of Lysine Content in Kernel and Relationship Between Lysine Content and Yield in Maize

This study aimed at seeking the genetic possibility of coinstantaneous improvement of kernel yield and lysine content in maize (Zea mays L.). Fifteen inbred lines selected from 5 basic maize populations were crossed with 5 elite inbred lines derived from different heterotic groups according to the NCII design. In 2009, 75 combinations were evaluated in Zhengzhou and Xuchang, Henan Province, China. The lysine contents in kernels of parents, F₁, and F₂ populations were determined using near infrared reflectance spectroscopy (NIRS) method, and analyzed in the model of triploid seed endosperm-cytoplasm-maternal effect. In addition to the 3 genetic systems of seeds, maternal effect, and cytoplasm effect as the predominating element, environmental factor was also found to affect the lysine content in kernels. The genetic main-effect (V_G), which was composed of 24.6% seed effect (V_A+V_D), 19.7% cytoplasm effect (V_C), and 55.7% maternal effect (V_Am+V_Dm), explained 76.3% of the total genetic variance (V_G+V_GE). The maternal heritability for lysine content (40.98%) was much higher than the seed heritability (17.86%) and cytoplasm heritability (14.29%). Besides, no significant correlation was found between the lysine content and grain yield (r = −0.0269, P > 0.05). Therefore, it is feasible to improve both kernel yield and lysine content simultaneously in maize breeding. In breeding practice, the parental lines with high lysine content, especially the female line, are the genetic basis, and diverse crosses among parents in different heterotic groups provide a wide platform for selecting both high yield and lysine content in the progenies.