Molecular and morphological evidence for resistance to sugarcane aphid (Melanaphis sacchari) in sweet sorghum [Sorghum bicolor (L.) Moench]

Abstract

Aphids are one of the devastating pests affecting the productivity of sorghum in many countries. The aim of the present investigation was to identify sweet sorghum genotypes resistant to the sugarcane aphid, Melanaphis sacchari (Zehntner). A Sequence Characterized Amplified Region (SCAR) marker linked to an aphid-resistance gene (RMES1) was first used to prescreen for resistant genotypes in 561 sorghum accessions. Molecular assays indicated that 91 sorghum accessions in the collection had the RMES1 resistance marker allele. Of those, 26 agronomically superior sweet sorghum accessions, along with three commercial cultivars and one susceptible check, were further evaluated in two locations (Antalya, a lowland province, and Konya, a highland province) under field conditions. These accessions were scored for resistance to aphid damage under natural aphid infestations. The number of aphids counted on the plant leaves and stalks in the accessions during the growing seasons was used to score resistant genotypes on a scale of 1-5, where 1 was highly resistant (plants having 0-50 aphids/ plant) and 5 was highly sensitive (plants having 1000 + aphids/plant). Fumagine intensity on the leaves was also taken into consideration. Ten accessions from the lowland and one accession from the highland scored "1," indicating a high resistance to aphid infestation. A further 13 accessions scored "1" or "2" in both environments. Only two accessions scored "4," and no accession scored "5," indicating the utility of the RMES1 marker for prescreening purposes. One accession, BSS507, showed outstanding resistance to M. sacchari, with a score of "1" in both environments.

Evaluation of sweet sorghum genotypes for bioethanol yield and related traits

“…The sorghum collection consisting of 551 sorghum accessions that were evaluated in this study was detailed in a previous study by Guden et al 30 . Of 551 accessions, 309 accessions from over 28 countries were supplied by the United States Department of Agriculture (USDA), and 242 accessions, including a sorghum mini core collection, 31 were provided from the International Crops Research Institute for the Semi‐Arid Tropics (ICRISAT) gene banks.…”

Electroactivity of polyphenols in sweet sorghum (Sorghum bicolor (L.) Moench) cultivars

“…Trans-aconitic acid was highly sensitive to spectrophotochemical detection by fluorescence excitation-emission (EEM) and UV/visible absorption, within the wavelength ranges overlapping with polyphenols [ 8 ]. Trans-aconitic acid and polyphenols [ 9 ] in juice, riboflavin-like fluorophore in bagasse [ 8 ], and dhurrin (tyrosine-derived cyanogenic glycoside) in leaves [ 10 ] are all candidate allelochemicals against aphids. Electrochemistry-based fingerprinting methods are necessary to understand the importance of redox-active defense phytochemicals.…”

Traits and underlying genetics important for low‐input organic sorghum production

“…Fortunately, lines and hybrids with a favorable allele for RMES1 , a known source of aphid tolerance (Boyles et al., 2019; Chang et al., 2012), displayed strong SCA tolerance across site‐years (Table 2). Host plant resistance was not present in any of the 10 sweet sorghum cultivars in the study; however, a number of sweet sorghum lines with SCA tolerance from RMES1 have been previously identified (Guden et al., 2019). Because simple sugars are both the desired yield product of sweet sorghum and the primary target source of the aphid, it is rational to heavily focus on improving SCA tolerance in adapted sweet sorghum cultivars.…”