Diversity in root traits of sorghum genotypes in response to Striga hermonthica infestation

Abstract

Striga hermonthica is a major biotic constraint to agriculture in the lowland areas of Ethiopia where sorghum is a major stable crop. A pot and a field experiment were conducted in 2011 during the rainy season using 10 sorghum genotypes. Each experiment had infested and non-infested conditions as the main plots and the 10 genotypes as subplots. The aim of this study was to examine the response of root traits of the sorghum genotypes to S. hermonthica infested conditions and to investigate relationships among S. hermonthica, root and growth traits of sorghum genotypes. Sorghum genotypes were categorized in to three groups, that is, low, moderate and high S. hermonthica count groups. Each group showed a differential response to root traits. Low S. hermonthica count groups had significantly lower root length, root length density, root to shoot ratio and root dry weight compared with susceptible groups. In contrast to low S. hermonthica count groups, moderate S. hermonthica count groups had higher root length, root length density, root to shoot ratio and root dry weight. Highly significant and strong relations were observed among root traits of sorghum, indicating that any of the root traits can be used as indicators for resistance. The result indicates different reactions in root traits in the upper soil layer may be useful for genetic improvement of S. hermonthica resistance and tolerance breeding in sorghum.

The soil microbiome modulates the sorghum root metabolome and cellular traits with a concomitant reduction of Striga infection

“… 42 Establishment of sorghum lines with constitutive suberin and aerenchyma production could provide support for these hypotheses. Despite prior reports that RSA is associated with Striga resistance, 43 , 44 , 45 we observed no effect of the soil microbiome on RSA traits measured here ( Figure 3 A).…”

The Soil Microbiome Reduces Striga Infection of Sorghum by Modulation of Host-Derived Signaling Molecules and Root Development

“…Whether this anatomical trait may be an additional postattachment resistance mode of other sorghum genotypes remains to be tested. Despite prior reports that root system architecture is associated with Striga resistance (Cherifari et al, 1990;Abate et al, 2017;Burridge et al, 2017), we observed no effect of the soil microbiome on RSA traits measured here (Fig. 3A).…”

Genotypic Variation in Cultivated and Wild Sorghum Genotypes in Response to Striga hermonthica Infestation

“…In our investigation, both field trials and inoculated pots were used to take care of natural infection conditions, as well as enhance uniformity of infection. There are a number of successful Striga studies that used both field and pot experiments together with supplemented artificial inoculation in the same way (Kountche et al, 2013 ; Rodenburg et al, 2015 ; Midega et al, 2016 ; Abate et al, 2017 ). Other studies also made use of pot experiments as Striga -free control (Samejima et al, 2016 ), or to enable the isolation of root exudates (Jamil et al, 2011 ; Hooper et al, 2015 ).…”

“…Recommended methodologies for effective field screening include inoculation with Striga seeds, appropriate experimental designs with sufficient replications, quantitative data scoring, and inclusion of susceptible and resistant checks at regular intervals (Haussmann et al, 2000b;Rodenburg et al, 2005). A quantitative measure such as "area under Striga number progress curve" (ASNPC) alongside Striga count, Striga vigor, and grain yield has been used in past studies (Haussmann et al, 2012;Abate et al, 2017) with great success. The aim of this study was to screen for novel sources of resistance to Striga using both wild and landrace sorghum accessions, improved sorghum varieties, selected F 4 progenies, and known Striga-resistant sources, such as N13, FRAMIDA, HAKIKA, IS9830, and SRN39, as checks.…”