Identification of quantitative trait loci (QTL) controlling fiber content of sugarcane (Saccharum hybrids spp.)

Authors: Islam, Md; Pan, Yong-Bao; Lomax, Lionel; Grisham, Michael

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2021
Publication Date: 3/19/2021
Publication URL: https://handle.nal.usda.gov/10113/7346834
Citation: Islam, M.S., Pan, Y.-B., Lomax, L.E., Grisham, M.P. 2021. Identification of quantitative trait loci (QTL) controlling fiber content of sugarcane (Saccharum hybrids spp.). Plant Breeding. 140(2):360-366. https://doi.org/10.1111/pbr.12912.
DOI: https://doi.org/10.1111/pbr.12912

Interpretive Summary: Fiber and sugar contents are two important traits for both sugar and energy production industries. Higher fiber content (FC) favors the energy production while lower FC facilitates the efficient sugar extraction in the mills. A favorable partition between sugar and fiber is essential for a good sugarcane crop stand and profitable sugar mill operation. However, it is very difficult to balance the two traits in a single genotype due to the complexity and large size of the sugarcane genome. The objective of this study was to identify molecular marker(s) for FC to help select improved sugarcane cultivars with favorable partition of FC. To do this, a superior sugarcane cultivar LCP 85-384 and its 142 progenies obtained by self-pollination were used in the study. FC data were collected from two crops (plant cane and first ratoon). Variations in FC values among LCP 85-384 and the 142 self progenies were analyzed along with an enriched genetic linkage map from this group. A total of five unique quantitative trait loci (QTL) molecular markers were identified across both crop cycles and combined, of which three QTL (qFC020, qFC044, and qFC053) were common explained a total of 22.46, 23.93, and 25.14 % of the FC variations for plant cane, first ratoon and combined data, respectively. As FC values increased gradually, the combined QTL effect also increased. We believe the QTL markers identified in this study could be novel for FC in sugarcane. Since the positive additive genetic effect will increase the FC value gradually in the presence of these three QTL markers..Use of these common QTL markers would benefit the breeders by selecting sugarcane lines with a balanced sugar and fiber partition.

Technical Abstract: The fiber content (FC) of sugarcane millable stalks is conversely important for both sugar and bioenergy production. Higher FC favors the energy producer while lower FC facilitates the efficient extraction in the sugar mills. A molecular marker for FC could help select improved sugarcane cultivars with favorable partitioning of FC for both sugar and energy production industries. A quantitative trait loci (QTL) study was conducted on a self-progeny population of LCP 85-384, an important cultivar in the pedigree of many Louisiana sugarcane cultivars. An enriched linkage map constructed with 967 simplex and duplex markers along with FC data from two crop cycles (plant cane and first ratoon) was used in this study. A total of five unique QTL were identified across both crop cycles and combined, of which three QTL (qFC020, qFC044, and qFC053) were common explained a total of 22.46, 23.93, and 25.14 % of the phenotypic variances for plant cane, first ratoon and combined data, respectively. As FC values increased gradually, the QTL allele combination effect also increased. Using markers linked to these putative common QTL alleles would benefit the breeders to select sugarcane lines for sugar and bioenergy production.