Heterosis plays an important role in switchgrass (Panicum virgatum L.) breeding. To identify superior clones for hybrid development through seasonal single cut, 10 crosses derived from ‘Alamo’ × ‘Kanlow’ and parents were evaluated. The experiment was planted in 2018 using a randomized complete block design with two replications at two locations in Tennessee: the East Tennessee Research and Education Center (ETREC), Knoxville, and the Plateau Research and Education Center (PREC), Crossville. The crosses and their parents were evaluated for biomass yield, plant height, and clonal mass in the fall of 2019 and 2020. The crosses were significantly different in biomass yield within and across locations (P ≤ .05). Average biomass yield of the crosses ranged from 7.1 to 8.7 Mg ha⁻¹ at ETREC and from 10.0 to 11.8 Mg ha⁻¹ at PREC. The crosses demonstrated an average of 46% mid-parent heterosis (MPH) and 24% high-parent heterosis (HPH) for biomass yield across the two locations. The MPH and HPH were 3 and −1.3% for plant height and 12 and 1% for clonal mass, respectively. Moderate to strong positive association was found between clonal mass scores and biomass yield at individual locations across years and across locations and years (r = 0.37–0.79, P ≤ .05). The association between biomass yield and plant height was inconsistent (r = −0.24 to 0.67, P ≤ .05). The findings of biomass yield heterosis in these crosses suggested the potential of hybrid cultivars for biomass yield improvement in lowland switchgrass.

中文翻译：

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'Alamo' × 'Kanlow'柳枝稷种群中生物量产量和其他性状的杂种优势

杂种优势在柳枝稷（Panicum virgatum L.）育种中起着重要作用。为了通过季节性单切鉴定杂交发育的优良克隆，评估了来自'Alamo'×'Kanlow'和亲本的10个杂交。该试验于 2018 年使用随机完整区组设计进行，在田纳西州的两个地点进行了两次重复：东田纳西州研究和教育中心 (ETREC)，诺克斯维尔，以及高原研究和教育中心 (PREC)，克罗斯维尔。2019 年和 2020 年秋季对杂交及其亲本进行了生物量产量、株高和克隆质量的评估。杂交在不同地点和地点之间的生物量产量差异显着（P ≤ .05）。杂交的平均生物量产量为 7.1 至 8.7 毫克公顷^-1在 ETREC 和从 10.0 到 11.8 Mg ha ^-1在 PREC。杂交表明两个地点的生物量产量平均为 46% 的中亲杂种优势 (MPH) 和 24% 的高亲杂种优势 (HPH)。植物高度的 MPH 和 HPH 分别为 3% 和 -1.3%，克隆质量分别为 12% 和 1%。在不同年份以及不同地点和年份的各个地点的克隆质量评分和生物量产量之间发现中度至强正相关（r = 0.37–0.79，P ≤ .05）。生物量产量与株高之间的关联不一致（r = -0.24 to 0.67, P≤ .05）。这些杂交中生物质产量杂种优势的发现表明杂交品种在提高低地柳枝稷的生物质产量方面具有潜力。