Development of Sorghum Genotypes for Improved Yield and Resistance to Grain Mold Using Population Breeding Approach

The infection caused by grain mold in rainy season grown sorghum deteriorates the physical and chemical quality of the grain, which causes a reduction in grain size, blackening, and making them unfit for human consumption. Therefore, the breeding for grain mold resistance has become a necessity. Pedigree breeding has been widely used across the globe to tackle the problem of grain mold. In the present study, a population breeding approach was employed to develop genotypes resistant to grain mold. The complex genotype × environment interactions (GEIs) make the task of identifying stable grain mold-resistant lines with good grain yield (GY) challenging. In this study, the performance of the 33 population breeding derivatives selected from the four-location evaluation of 150 genotypes in 2017 was in turn evaluated over four locations during the rainy season of 2018. The Genotype plus genotype-by-environment interaction (GGE) biplot analysis was used to analyze a significant GEI observed for GY, grain mold resistance, and all other associated traits. For GY, the location explained a higher proportion of variation (51.7%) while genotype (G) × location (L) contributed to 21.9% and the genotype contributed to 11.2% of the total variation. For grain mold resistance, G × L contributed to a higher proportion of variation (30.7%). A graphical biplot approach helped in identifying promising genotypes for GY and grain mold resistance. Among the test locations, Dharwad was an ideal location for both GY and grain mold resistance. The test locations were partitioned into three clusters for GY and two clusters for grain mold resistance through a “which-won-where” study. Best genotypes in each of these clusters were selected. The breeding for a specific cluster is suggested. Genotype-bytrait biplots indicated that GY is influenced by flowering time, 100-grain weight (HGW), and plant height (PH), whereas grain mold resistance is influenced by glume coverage and PH. Because GY and grain mold score were independent of each other, there is a scope to improve both yield and resistance together

Sequence Conservation in the Coat Protein Gene of Tobacco streak virus Isolates Causing Necrosis Disease in Cotton, Mung bean, Sunflower and Sunn-hemp in India

350-356Natural infection of Tobacco streak virus (TSV) in cotton, mung bean, sunflower and sunn-hemp, collected from different locations in India, was detected by reverse transcription-polymerase chain reaction (RT-PCR). The coat protein (CP) gene sequences of the six TSV isolates originating from different hosts and locations were amplified. The resulting amplicons were cloned and sequenced to assess molecular variability. The sequence and phylogenetic analyses revealed that the CP gene among TSV isolates collected from different hosts and locations was highly conserved (99-100%), suggesting a common origin

Mycoparasitism of Alternaria alternata by an Additional Eight Fungi Indicating the Existence of Further Unknown Candidates for Biological Control

In studies using light and scanning electron microscopy it was clearly demonstrated that Nectria inventa, Gliocladium roseum, G. ca.tenula.tum, Clonostacbys sp., Sesquidllium sp., Verticillium nigrescens, Dicyma olivacea, Stachybotrys elegans, Myrothecium carmichaelii, M. cinctum, M. roridum, M. tongaense, M. verrucaria and Coniothyrium sporulosum are able to parasitize Alternaria alternata. With the exception of N. inventa and the five Myrothecium spp., none of the other fungi has been previously reported to be mycoparasitic on Alternaria. Moreover, there is no current information about the mycoparasitic and antibiotic activity of the genera Clonostacbys and Sesquici-lium. The mode of parasitism was nearly the same in all of the mycoparasites. In many cases, penetration was achieved directly by the hyphal tips without the formation of appressorium like structures (ALS) and there was no evidence that the formation of ALS was a prerequisite for penetration. Dependant on the severity of infection, a gradual shrinkage, distortion and an eventual collapse of the parasitized conidia were observed. A bursting and total collapse of the spores without any penetration was detected by the antibiotic producing mycoparasites such as G. roseum, G. CAtenulatum, Clonostacbys sp., Sesquicillium sp., D. olivacea and the five Myrothecium species. In consideration of their activity, all of the tested antagonists would appear to be candidates for in vivo investigations to check their suitability as biocontrol agents. Copyright © 1993, Wiley Blackwell. All rights reserve