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Flooding tolerance in maize (Zea mays subsp. mays) F1 hybrids containing a QTL introgressed from teosinte (Zea nicaraguensis)

Mano, Y., Omori, F.
Euphytica 2015 v.205 no.1 pp. 255-267
Zea mays subsp. mays, Zea nicaraguensis, chromosomes, climate change, corn, crop yield, cultivars, developmental stages, flooding tolerance, heterozygosity, homozygosity, hybrids, introgression, leaves, plant breeding, quantitative trait loci, risk, roots, shoots, soil, starch
Worldwide climate change has increased the risk of crop yield losses caused by flooding. Here, we report the development of maize F₁ hybrids containing a teosinte QTL for flooding tolerance on chromosome 4 and the evaluation of flooding tolerance under reducing soil conditions. We used F₁ hybrid Mi29 × Mi47 (cultivar Yumechikara) and two versions of Yumechikara into which the QTL has been introgressed, Mi47 × IL#18 (heterozygous for the QTL) and IL#18 × BC₃#90 (homozygous for the QTL). Flooding tolerance was evaluated at three treatment levels (i.e., soluble starch at 1, 0.5 or 0 g L⁻¹) and the non-flooded control at an early growth stage (2.6- to 3.0-leaf stage) and at the 5.5-leaf stage. Tolerance was assessed by measuring leaf injury, leaf SPAD values, and shoot and root dry weight ratios (treatment/control). The F₁ hybrids containing the QTL were significantly more tolerant (as evaluated by leaf injury and SPAD values) than the original F₁ cultivar (Mi29 × Mi47) at both growth stages. When flooding tolerance was evaluated by shoot dry weight ratio at an early growth stage, IL#18 × BC₃#90 was significantly more tolerant than Mi29 × Mi47 at the 1 and 0 g L⁻¹ treatment levels. At the 5.5-leaf stage, there were no significant differences among the three F₁ hybrids under the three treatment levels. Although plants at an early growth stage are generally more sensitive to flooding than at later stages, IL#18 × BC₃#90 should overcome flooding stress at the sensitive early stage of growth.