Belum V. S. Reddy

Bio-Fuel Crops Research for Energy Security and Rural Development in Developing Countries

Soaring prices of fossil fuels, geo-political issues and environmental pollution associated with fossil fuel use has led to worldwide interest in the production and use of bio-fuels. Both the developed and developing countries have developed a range of policies to encourage production of combustible fuels from plants that triggered public and private investments in bio-fuel crop research and development, and bio-fuels production. In this article, we discuss the potential benefits of bio-fuels in increasing the farmers’ incomes, reducing environment pollution, the crop options and research and development interventions required to generate feedstocks to produce bio-fuels to meet projected demand without compromising food/fodder security in developing countries.

Screening sorghum genotypes for salinity tolerant biomass production

Genetic improvement of salt tolerance is of high importance due to the extent and the constant increase in salt affected areas. Sorghum [Sorghum bicolor (L.) Moench] has been considered relatively more salt tolerant than maize and has the potential as a grain and fodder crop for salt affected areas. One hundred sorghum genotypes were screened for salinity tolerance in pots containing Alfisol and initially irrigated with a 250-mM NaCl solution in a randomized block design with three replications. Subsequently 46 selected genotypes were assessed in a second trial to confirm their responses to salinity. Substantial variation in shoot biomass ratio was identified among the genotypes. The performance of genotypes was consistent across experiments. Seven salinity tolerant and ten salinity sensitive genotypes are reported. Relative shoot lengths of seedlings were genetically correlated to the shoot biomass ratios at all stages of sampling though the relationships were not close enough to use the trait as a selection criterion. In general, the whole-plant tolerance to salinity resulted in reduced shoot Na+ concentration. The K+/Na+ and Ca2+/Na+ ratios were also positively related to tolerance but with a lesser r2. Therefore, it is concluded that genotypic diversity exists for salt tolerance biomass production and that Na+ exclusion from the shoot may be a major mechanism involved in that tolerance.

Development of screening methods and identification of stable resistance to anthracnose in sorghum

Effective greenhouse- and field-screening techniques were developed to identify resistance to anthracnose (Colletotrichum graminicola) in grain sorghum (Sorghum bicolor). In greenhouse screening, sorghum plants were spray-inoculated at the 6–8 leaf stage with a conidial suspension (4 × 105 conidial ml−1) of C. graminicola. Inoculated plants were incubated in a high humidity chamber (⩾ 90% RH) for 24 h at 25–28°C and relocated to a greenhouse at 25 ± 2°C. Anthracnose development was scored 7–8 days after inoculation. In the field-screening technique, in every fifth row, a highly anthracnose-susceptible sorghum line was sown as an infector row. Ten days later, test lines were sown between infector row plants were inoculated at the 6–8 leaf stage with either spore suspension or by dropping infected sorghum grains into the leaf whorl. High humidity was provided by frequent overhead sprinkler or furrow irrigation. Test lines were scored for anthracnose development at the hard-dough stage. Significant positive correlation (r = 0.88, P < 0.001) was found for anthracnose severity between seedling screening in greenhouse and adult plant screening in the field. The field-screening technique was successfully transferred to several locations in Africa and India. Thirty lines were selected from more than 13 000 sorghum germplasm accessions and advanced breeding lines screened for anthracnose resistance, using the field-screening technique at Pantnagar (North India) between 1982 and 1991. They were evaluated in multilocational tests at hot spots in Burkina Faso, India, Nigeria, Zambia, and Zimbabwe for 1–10 years. Eleven lines (A 2267-2, IS 3547, IS 8283, IS 9146, IS 9249, IS 18758, SPV 386, PB 8892-2, PS 18601-3, PM 20873-1, and M 35610) showed stable resistance across these locations over the years. Some of the resistant lines are being converted into male-sterile lines through backcrossing with different sources of cytoplasmic male sterility.

Improving the production and utilization of sorghum and pearl millet as livestock feed: methodological problems and possible solutions

Abstract The overall objective of this work was the identification of simple, yet accurate, assessments of fodder quality of sorghum and pearl millet stover in crop improvement programs. Stover from 12 genotypes of sorghum and six genotypes of pearl millet grown under high and low fertilizer application was investigated for nitrogen, cell wall constituents, sugar, plant height, stem diameter, leaf number per plant and extent and rate of in vitro gas production of whole stover and of stover cell walls. Organic matter digestibility, organic matter intake, digestible organic matter intake (DOMI) and cell wall digestibility were measured in bulls. Significant genotypic variation was found for chemical, morphological and in vitro fermentation characteristics of stover but their relationship with digestibility and intake measurements was generally poor. While no single chemical, morphological or in vitro measurement described stover quality adequately, some combinations of these measurements resulted in good overall relationships with stover quality measurements. Across sorghum and pearl millet, 71% (P

Analysis of resistance to Striga hermonthica in diallel crosses of sorghum

Parasitic flowering weeds of the genus Striga aremajor biotic constraints to sorghum (Sorghum bicolor(L.) Moench) production in sub-Saharan Africa. The agar-gel assay was used to evaluate stimulation ofStriga hermonthica (Del.) Benth. seed germination by a complete F1 diallel involving nine sorghum cultivars and inbred lines. Striga populations from Mali and Niger were employed. The same genetic materials were planted in pot trials in both countries to observe striga plant emergence. Variation in hybrid performance was determined by general (GCA) and specific combining ability (SCA) effects, with preponderance of GCA, for both germination distance in the agar-gel assay and number of emerged striga. Reciprocal effects were significant only in the agar-gel assay and were unstable across striga populations. For lines and hybrids, estimates of broad-sense heritabilities were 0.97 and 0.91 for germination distance, and 0.38 and 0.58 for emerged striga, respectively. Only a weak positive relationship existed between in vitro germination distance and emerged striga number in the pot trial. Although selection for low germination distance has merit, valuable material with resistance mechanisms other than low stimulant production may be lost if these traits are not additionally assessed. Laboratory assays which allow a non-destructive, quick and economical screening for resistance mechanisms other than the low stimulant character are likely to increase the efficiency of breeding programs for striga resistance. The significant contribution of SCA effects indicates that thorough screening of testcrosses is indispensable for selection in hybrid sorghum breeding programs.

Relative susceptibility of different male-sterile cytoplasms in sorghum to shoot fly, Atherigona soccata

SummaryThe shoot fly, Atherigona soccata is an important pest of sorghum, and host plant resistance is one of the most effective components for managing this pest. Most of the hybrids grown in India based on milo cytoplasm (A1 cytoplasm) are highly susceptible to shoot fly. Therefore, the present studies were undertaken to evaluate different male-sterile cytoplasms (CMS) for their relative susceptibility to sorghum shoot fly. Oviposition and deadheart formation were significantly lower on the maintainer lines as compared to the corresponding male-sterile lines. Among the cytoplasms tested, A4M cytoplasm showed antixenosis for oviposition and suffered lower deadheart formation than the other cytoplasms tested. The A4G1 and A4M cytoplasms suffered lower deadhearts in tillers than the other cytoplasms. Recovery following shoot fly damage in A4M, A3, and A2 cytoplasms was better than in the other cytoplasms tested. The larval and pupal periods were longer and male and female pupal weights lower in A4M and A4VzM CMS backgrounds compared to the other CMS systems. Fecundity and antibiosis indices on CMS lines were lower than on the B-lines. The A4M cytoplasm was found to be relatively resistant to sorghum shoot fly, and can be exploited for developing shoot fly-resistant hybrids for sustainable crop production in future.

Combining ability and heterosis as influenced by male-sterility inducing cytoplasms in sorghum [Sorghum bicolor (L.) Moench]

An investigation was carried out to assess the efficiency of A2 cytoplasmic-nuclear male-sterility (CMS) system in comparison to the widely used A1 cytoplasm in terms of general combining ability (gca) effects of male-sterile (A-) lines and mean performance, specific combining ability (sca) effects and mid-parent heterosis of hybrids for days to 50% flowering, plant height and grain yield at International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India in 2001 and 2002 rainy seasons. The material for the study consisted of six pairs of iso-nuclear, allo-plasmic (A1 and A2) A-lines and 36 iso-nuclear hybrids produced by crossing these A-lines with three dual restorer (R-) lines. The results revealed that cytoplasm and its first-order interaction with year, R- and A-lines did not appear to contribute to variation in iso-nuclear hybrids for plant height and grain yield. Cytoplasm had limited effect on gca effects of A-lines and on sca effects and mid-parent heterosis of iso-nuclear hybrids for days to 50% flowering, plant height and grain yield. The mean days to 50% flowering, plant height and grain yield of A2 cytoplasm-based hybrids were comparable with those of widely used A1 cytoplasm-based hybrids. The relative frequency of the occurrence of the A1- and A2-based hybrids with significant sca effects and mid-parent heterosis indicated that A2 CMS system is as efficient as A1 with a slight edge over A1 for commercial exploitation. The implications of these results are discussed in relation to opportunities for broadening not only cytoplasm base but also nuclear genetic base of both the hybrid parents.

Synthesis and characterization of gold glyconanoparticles functionalized with sugars of sweet sorghum syrup

Gold glyconanoparticles were synthesized by a simple, rapid, and eco‐friendly method by using sweet Sorghum syrup for application in biomedicine and biotechnology. The nanostructures of the prepared gold nanoparticles were confirmed by using UV‐visible absorbance, TEM, SAED, FTIR, EDAX, XRD, and photoluminescence analyses. The formation of gold nanoparticles at both room and boiling temperatures and kinetics of the reaction were monitored by UV‐visible spectroscopy and TEM studies. TEM analysis revealed that the obtained nanoparticles were mono‐dispersed and spherical in shape with an average particle size of 7 nm. The size of the nanoparticles was influenced by the concentration of Sorghum syrup. The presence of elemental gold was confirmed by EDAX analysis. Based on the FTIR analysis, it was observed that the sugars present in the Sorghum syrup possibly acts as capping agents. The zeta potential analysis revealed that the glyconanoparticles were negatively charged with a potential of −25 mV. The XRD and SAED patterns also suggest that the nanoparticles were crystalline in nature and these particles were found to exhibit visible photoluminescence. Fructose and glucose present in sweet Sorghum syrup were demonstrated as responsible sugars for the reduction of gold ions, and sucrose stabilized the formed nanoparticles. The proposed mechanism for the formation and stabilization of gold glyconanoparticles is based on the phenomenon of “macromolecular crowding.” This is the first report on the use of sweet Sorghum syrup for the green synthesis of gold glyconanoparticles at both room and boiling temperatures.

Feasibility of sustaining sugars in sweet sorghum stalks during post-harvest stage by exploring cultivars and chemicals: a desk study.

In the recent years sweet sorghum is emerging as an important feedstock for bioethanol production. It was observed that total soluble sugar yield (TSSY) increases with time in the post-anthesis phase depending on the length of crop cycle. The qualitative and quantitative sugar loss of up to 50% or more occurs due to delay in harvest during post-physiological maturity stage depending on the genotype, weather and soil conditions, and the time lag between harvest and crushing of the stalks. Hence, a desk study was conducted to identify suitable cultivars and/or explore the use of chemicals that sustain sugars in the post-harvest phase. In case of delayed harvest beyond physiological maturity stage, growing of cultivars such as SPSSV 30, ICSV 25275, ICSV 25280 and SPV 422 that sustain sugar yield at post-physiological maturity, is recommended. As there are no published reports on sweet sorghum, the literature from sugarcane and wine industries were analyzed and inferences drawn from these industries suggest the evaluation of chemicals like sodium benzoate, potassium metabisulphate, sodium metabisulphite, ammonia, SO2, vanillin and acetic acid (vinegar) which may arrest the post-harvest deterioration of sweet sorghum stalks before juice extraction.

Sweet Sorghum: Breeding and Bioproducts

Sorghum [Sorghum bicolor (L.) Moench] is the fifth most important cereal crop and is the dietary staple of more than 500 million people in over 90 countries, primarily in the developing world. However, sweet sorghum which is similar to grain sorghum except for accumulation of stalk sugars, is considered as a potential energy crop without impacting the food security of millions. Further, the sorghum stover is considered to be a potential lignocellulosic biofuel feedstock. Being a C4 plant, it has high photosynthetic rate, and several mechanisms are known to confer resilience that help produce higher yield in varied environmental conditions. This chapter not only discusses different breeding methodologies for improving candidate sugar and biomass traits but also the possible utilization of this smart feedstock for diverse biochemicals (lactic acid, xylitol, glycerol, etc.) and bioproducts (nanomaterials, anticancer and microbial compounds, adhesives, polymers, antidiabetic compounds, etc.) development.