Application GGE biplot and AMMI model to evaluate sweet sorghum (Sorghum bicolor) hybrids for genotype x environment interaction and seasonal adaptation,”

ABSTRACT The genotype × environment interaction influences greatly the success of breeding strategy in a multipurpose crop like sweet sorghum [Sorghum bicolor (L.) Moench]. Eleven improved sweet sorghum hybrids were evaluated in both seasons for three years and genotype main effects and genotype × environment interaction (GGE) biplot analysis revealed that the hybrids that performed well in rainy season are: 'ICSSH 24' and 'ICSSH 39' and post rainy season are: 'ICSSH 57' and 'ICSSH 28'. The stable hybrid, based on additive main effects and multiplicative interaction (AMMI) and GGE biplot analysis that performed well across seasons and over the years for grain yield and stalk sugar yield is: 'ICSSH 28'

Biological Nitrification Inhibition (BNI) Potential in Sorghum

The biological oxidation of ammonia (i.e. nitrification), results in the transformation of relatively immobile NH4+ into a highly mobile NO3-, which is vulnerable to losses through leaching and denitrification, resulting in low nitrogen-use efficiency in agricultural systems. The ability of certain plants to suppress soil nitrifier function by releasing inhibitors from roots is termed 'biological nitrification inhibition' (BNI). Using a recombinant luminescent Nitrosomonas europaea, we developed an assay to detect and quantify the inhibitory effects in plant soil systems termed, 'BNI activity', expressed in ATU (allylthiourea unit). Sorghum roots released (into water-based medium, hereafter referred to as root exudates) substantial amount of BNI activity. The BNI capacity (ATU g-1 root dry wt d-1) of roots changed with growth stage, from 60 ATU at 3 week old to 20 ATU at 45 day stage. In addition, sorghum roots released hydrophobic compounds, which can be recovered by washing with dichloromethane (hereafter referred to as DCM-root wash). One of the active constituents with BNI activity in root exudates, isolated by activity-guided HPLC fractionation, was a flavonoid, identified as sakuranetin. Using a similar approach, the major active constituent with BNI activity in DCM-root wash was isolated and identified as sorgoleone. Both sakuranetin and sorgoleone inhibited Nitrosomonas activity in a dose-response manner. Substantial genetic variability for sorgoleone production capacity was detected in sorghum. Some wild-sorghum species showed high-BNI capacity under field conditions. Potential implications of BNI in inhibiting nitrification and in reducing the nitrogen footprint from agricultural systems will be discussed

Biological Nitrification Inhibition (BNI) Potential in Sorghum

The biological oxidation of ammonia (i.e. nitrification), results in the transformation of relatively immobile NH4+ into a highly mobile NO3-, which is vulnerable to losses through leaching and denitrification, resulting in low nitrogen-use efficiency in agricultural systems. The ability of certain plants to suppress soil nitrifier function by releasing inhibitors from roots is termed 'biological nitrification inhibition' (BNI). Using a recombinant luminescent Nitrosomonas europaea, we developed an assay to detect and quantify the inhibitory effects in plant soil systems termed, 'BNI activity', expressed in ATU (allylthiourea unit). Sorghum roots released (into water-based medium, hereafter referred to as root exudates) substantial amount of BNI activity. The BNI capacity (ATU g-1 root dry wt d-1) of roots changed with growth stage, from 60 ATU at 3 week old to 20 ATU at 45 day stage. In addition, sorghum roots released hydrophobic compounds, which can be recovered by washing with dichloromethane (hereafter referred to as DCM-root wash). One of the active constituents with BNI activity in root exudates, isolated by activity-guided HPLC fractionation, was a flavonoid, identified as sakuranetin. Using a similar approach, the major active constituent with BNI activity in DCM-root wash was isolated and identified as sorgoleone. Both sakuranetin and sorgoleone inhibited Nitrosomonas activity in a dose-response manner. Substantial genetic variability for sorgoleone production capacity was detected in sorghum. Some wild-sorghum species showed high-BNI capacity under field conditions. Potential implications of BNI in inhibiting nitrification and in reducing the nitrogen footprint from agricultural systems will be discussed

Components of resistance to sorghum shoot fly, Atherigona soccata

Sorghum shoot fly, Atherigona soccata is one of the major constraints in sorghum production, and host plant resistance is one of the components to control sorghum shoot fly. Thirty sorghum genotypes were evaluated for different mechanisms of resistance and morphological and agronomic traits during the rainy and postrainy seasons. The sorghum genotypes, Maulee, Phule Anuradha, M 35-1, CSV 18R, IS 2312, Giddi Maldandi, and RVRT 3 suffered lower shoot fly damage, and also exhibited high grain yield potential during the postrainy season. ICSB 433, ICSV 700, ICSV 25019, ICSV 25022, ICSV 25026, ICSV 25039, PS 35805, Akola Kranti, and IS 18551 exhibited antixenosis for oviposition and antibiosis against sorghum shoot fly, A. soccata. Leaf glossiness, plant vigor, leafsheath pigmentation and trichomes were associated with resistance/susceptibility to shoot fly. Path coefficient analysis indicated that direct effects and correlation coefficients of leaf glossiness, plant vigor, plant height, plant color and trichomes were in the same direction, suggesting that these traits can be used to select sorghum genotypes for resistance to shoot fly. Principal co-ordinate analysis based on shoot fly resistance traits and morphological traits placed the test genotypes into different groups. The genotypes placed in different groups can be used to increase the levels and broaden the genetic base of resistance to shoot fly. The environmental coefficient of variation and phenotypic coefficient of variation for shoot fly resistance and morphological traits were quite high, indicating season specific expression of resistance to sorghum shoot fly. High broadsense heritability, genetic advance and genotypic coefficient of variation suggested the predominance of additive nature of genes controlling shoot fly resistance, suggesting that pedigree breeding can be used to transfer shoot fly resistance into high yielding cultivars. This information will be useful for developing shoot fly-resistant high yielding cultivars for sustainable crop production