Iseki Kohtaro, Matsumoto Ryo, Olaleye Olajumoke, Shimizu Motoki, Asfaw Asrat
Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Japan.
International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria.
Front Plant Sci. 2022 Apr 25;13:837951. doi: 10.3389/fpls.2022.837951. eCollection 2022.
White Guinea yam () is mainly a dioecious tuberous crop that produces flowers of varying sex phenotypes. Agronomic traits in Guinea yam differ according to the sex phenotype, but the precise interaction between the traits and sex phenotype is not clearly understood. This might be due to the high heterozygosity of yam where cultivars with different flowering sex have different genetic backgrounds, which mask the sole effect of sex phenotype on the agronomic traits. This study used F-derived clonal progenies from a bi-parental cross to minimize the impact of different genetic backgrounds among the plants with different sex phenotypes. The impact of plant sex on agronomic traits, specifically tuber yield, was evaluated through field trials conducted for four years. The results showed that only plants with a female genotype exhibited varying sex phenotypes even within the clones of same accession grown in the same experimental field. The significant effects of sex genotype and phenotype on agronomic traits were detected. Our results revealed that the flowering date was delayed in the plants with female genotypes compared to male genotypes, even when compared only among the plants with male phenotypes. The flowering date is the most important reason for the sexual differences in tuber yield. A high tuber yield was obtained when plants with the female phenotype flowered before tuber enlargement. This result can be attributed to the fact that the low flowering intensity in female plants increases the availability of carbon resources for leaf development. Female plants also showed a large negative effect of late flowering on tuber yield owing to resource competition between flowering and tuber enlargement. These findings demonstrate the feasibility of yield improvement by controlling the flowering time, with a higher effectiveness achieved in female than in male plants.
白薯蓣（）主要是一种雌雄异株的块茎作物，会产生不同性别表型的花朵。几内亚薯蓣的农艺性状因性别表型而异，但这些性状与性别表型之间的确切相互作用尚不清楚。这可能是由于薯蓣的杂合度高，不同开花性别的品种具有不同的遗传背景，这掩盖了性别表型对农艺性状的单一影响。本研究使用了双亲杂交产生的F代克隆后代，以尽量减少不同性别表型植株间不同遗传背景的影响。通过进行了四年的田间试验，评估了植株性别对农艺性状，特别是块茎产量的影响。结果表明，即使在同一试验田中种植的同一种质的克隆植株中，只有具有雌性基因型的植株表现出不同的性别表型。检测到性别基因型和表型对农艺性状有显著影响。我们的结果表明，与雄性基因型植株相比，具有雌性基因型的植株开花日期延迟，即使仅在具有雄性表型的植株之间比较也是如此。开花日期是块茎产量性别差异的最重要原因。当具有雌性表型的植株在块茎膨大前开花时，可获得较高的块茎产量。这一结果可归因于雌性植株开花强度低增加了用于叶片发育的碳资源可用性。由于开花与块茎膨大之间的资源竞争，雌性植株开花延迟对块茎产量也有很大的负面影响。这些发现证明了通过控制开花时间提高产量的可行性，雌性植株比雄性植株效果更好。
