ZmCCT haplotype H5 improves yield, stalk-rot resistance, and drought tolerance in maize

Lixiu Tong; Mingzhu Yan; Mang Zhu; Jie Yang; Yipu Li; Mingliang Xu

doi:10.3389/fpls.2022.984527

ZmCCT haplotype H5 improves yield, stalk-rot resistance, and drought tolerance in maize

Front Plant Sci. 2022 Aug 15:13:984527. doi: 10.3389/fpls.2022.984527. eCollection 2022.

Authors

Lixiu Tong¹, Mingzhu Yan¹, Mang Zhu¹, Jie Yang^{1

2}, Yipu Li^{1

3}, Mingliang Xu¹

Affiliations

¹ State Key Laboratory of Plant Physiology and Biochemistry, College of Agronomy and Biotechnology, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, China.
² Food Crops Research Institute, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
³ Agricultural College, Inner Mongolia Agricultural University, Hohhot, China.

Abstract

The ZmCCT locus underlies both stalk-rot resistance and photoperiod sensitivity in maize (Zea mays L.). We previously introduced nine resistant ZmCCT haplotypes into seven elite but susceptible maize inbred lines (containing the haplotype H1) to generate 63 backcross families. Here, we continued backcrossing, followed by selfing, to develop 63 near-isogenic lines (NILs). We evaluated 22 of these NILs for stalk-rot resistance and flowering time under long-day conditions. Lines harboring the haplotype H5 outperformed the others, steadily reducing disease severity, while showing less photoperiod sensitivity. To demonstrate the value of haplotype H5 for maize production, we selected two pairs of NILs, 83B28 ^H1 /83B28 ^H5 and A5302 ^H1 /A5302 ^H5 , and generated F₁ hybrids with the same genetic backgrounds but different ZmCCT alleles: 83B28 ^H1 × A5302 ^H1 , 83B28 ^H1 × A5302 ^H5 , 83B28 ^H5 × A5302 ^H1 , and 83B28 ^H5 × A5302 ^H5 . We performed field trials to investigate yield/yield-related traits, stalk-rot resistance, flowering time, and drought/salt tolerance in these four hybrids. 83B28 ^H5 × A5302 ^H1 performed the best, with significantly improved yield, stalk-rot resistance, and drought tolerance compared to the control (83B28 ^H1 × A5302 ^H1 ). Therefore, the ZmCCT haplotype H5 has great value for breeding maize varieties with high yield potential, stalk-rot resistance, and drought tolerance.

Keywords: ZmCCT; drought tolerance; hybrids; stalk-rot resistance; yield.