Heterosis in Switchgrass: Biomass Yield in Swards

Abstract

Improving the biomass yield of switchgrass (Panicum virgatum L.) will improve its utility as a dedicated energy crop by increasing both its net and total energy yield per hectare. In a previous space‐transplanted study, midparent heterosis for biomass yield was reported for population and specific F1 hybrids of the lowland‐tetraploid cultivar Kanlow and the upland‐tetraploid cultivar Summer. These two cultivars were proposed to be two different heterotic groups. The objective of this study was to determine the extent of heterosis for biomass yield in reciprocal Kanlow (K) and Summer (S) F1 population hybrids grown in simulated swards and to determine the effect of advance in generation on biomass yield. Parent populations and their F1, F2, and F3 population hybrids were grown in transplanted sward plots located near Mead, NE, for a three‐year period. Plant density in the simulated swards was equivalent to acceptable stands in seeded plots. Plots were not harvested the establishment year to enable them to become fully established. Biomass yields were determined for the following two years. There was significant high‐parent heterosis of 30 to 38% (P ≤ 0.01) for biomass yield for both the K × S F1 and S × K F1 hybrid populations. Heterosis for biomass yield declined with advance in generation. Heterosis for biomass yield in switchgrass may need the competitive conditions of swards to be fully expressed. Additional trials of specific hybrids established from seed are needed to further verify these conclusions. These results do provide ample justification for additional research to develop switchgrass population and specific hybrids.

Categories of Resistance to Greenbug and Yellow Sugarcane Aphid (Hemiptera: Aphididae) in Three Tetraploid Switchgrass Populations

“…Plant Material Two no-choice studies were performed to evaluate the categories and relative levels of antibiosis and tolerance of three switchgrass populations: Kanlow (lowland cultivar), Summer (upland cultivar) [3,39], and a third generation stabilized population of plants, hereafter referred to as K×S, originally derived by intermating Kanlow (male) and Summer (female) plants to produce hybrids [20,39]. Seeds for all populations were provided by Dr. Kenneth Vogel (USDA-ARS, Grain, Forage, and Bioenergy Research Unit, Lincoln, Nebraska).…”

Midwest vision for sustainable fuel production

“…Hybrids between Summer (upland) and Kanlow (lowland) were selected through three generations for survivorship and biomass yield, resulting in superior performance compared to either parent at a range of locations that spanned Plant Hardiness Zones 3 through 5 ( Table 1). The hybrids possessed a broader adaptation range than either of the parent cultivars and increased yield by 32 to 54% compared to the parent cultivars [77]. Future breeding efforts in Nebraska and Wisconsin are heavily leveraged toward the use of hybrid populations for continuing to create novel and significant genetic improvements to switchgrass (see Future Perspectives).…”

Post-glacial evolution of Panicum virgatum: centers of diversity and gene pools revealed by SSR markers and cpDNA sequences

“…The nearly obligate allogamous mating strategy of switchgrass encourages cross-pollination among diverse individuals and helps to preserve genetic diversity through a highly heterozygous genome (Martinez-Reyna and Vogel 2002;Vogel 2004). Pollination facilitated by wind further encourages cross-pollination between geographically and phenotypically diverse strains, leading to potentially heterotic effects from the combination of diverse and complimentary linkage blocks (Lamkey and Edwards 1999;Melchinger 1999;Vogel and Mitchell 2008). These forces resulted in a balance between migration, drift, and selection, creating phenotypic diversity across a broad landscape (McMillan 1959;Casler et al 2007b), but allowing continued migration to balance the effects of drift, maintaining large effective population sizes across a broad landscape.…”