Dual-purpose Varieties Research Articles

Genetic diversity analysis of a flax (Linum usitatissimum L.) global collection

BackgroundA sustainable breeding program requires a minimum level of germplasm diversity to provide varied options for the selection of new breeding lines. To maximize genetic gain of the North Dakota State University (NDSU) flax breeding program, we aimed to increase the genetic diversity of its parental stocks by incorporating diverse genotypes. For this purpose, we analyzed the genetic diversity, linkage disequilibrium, and population sub-structure of 350 globally-distributed flax genotypes with 6200 SNP markers.ResultsAll the genotypes tested clustered into seven sub-populations (P1 to P7) based on the admixture model and the output of neighbor-joining (NJ) tree analysis and principal coordinate analysis were in line with that of structure analysis. The largest sub-population separation arose from a cluster of NDSU/American genotypes with Turkish and Asian genotypes. All sub-populations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise Fst comparison revealed a great degree of divergence (Fst > 0.25) between most of the combinations. A whole collection mantel test showed significant positive correlation (r = 0.30 and p < 0.01) between genetic and geographic distances, whereas it was non-significant for all sub-populations except P4 and P5 (r = 0.251, 0.349 respectively and p < 0.05). In the entire collection, the mean linkage disequilibrium was 0.03 and it decayed to its half maximum within < 21 kb distance.ConclusionsTo maximize genetic gain, hybridization between NDSU stock (P5) and Asian individuals (P6) are potentially the best option as genetic differentiation between them is highest (Fst > 0.50). In contrast, low genetic differentiation between P5 and P2 may enhance the accumulation of favorable alleles for oil and fiber upon crossing to develop dual purpose varieties. As each sub-population consists of many genotypes, a Neighbor-Joining tree and kinship matrix assist to identify distantly related genotypes. These results also inform genotyping decisions for future association mapping studies to ensure the identification of a sufficient number of molecular markers to tag all linkage blocks.

Terminal drought effect on sugar partitioning and metabolism is modulated by leaf stay-green and panicle size in the stem of sweet sorghum (Sorghum bicolor L. Moench)

BackgroundThe benefits of leaf stay-green for maintaining grain filling in sorghum under drought was largely demonstrated. However, its role in the stability of a dual production (grain, stem sugar) in tall sweet sorghum remains to be elucidated. This study aimed to analyze the impact of a post-anthesis drought on sugar accumulation along stem internodes in sweet and tall West-African sorghum with variable leaf stay-green and grain yield abilities.MethodsFour accessions with similar phenology were studied in two consecutive years in the field at the National Agronomic Research Centre (CNRA) of Bambey (Senegal, West Africa) under two post-anthesis water treatments (irrigated, non-irrigated). Plant morphology, stem sugar related traits, grain production, and plant leaf area (PLA) variation were assessed. Carbohydrate contents (sucrose, hexoses, starch) were determined during grain filling in the whole stem juice and at three internode levels: bottom, median, top. Analysis of variance was performed to test post-anthesis water treatment, accession, organ, year effects and their interactions on the studied traits.ResultsPanicle dry weight (PDW) was not affected by drought, but strongly varied among years and accessions. The PDW/PLA ratio was negatively correlated with the variation of sucrose and hexoses at the three internodes levels. This carbohydrates reduction was mainly influenced by the PDW. The bigger the panicle the higher the carbohydrates remobilization from the stem to panicle for grain filling. This was mainly shown on accessions G3 and G11 which exhibited low stay green ability. However, G10 with low PDW/PLA ratio and showing higher stay green ability, exhibited a low reduction of total soluble sugars and sucrose and inversely higher increase of hexoses mainly at the median internode.ConclusionsThis ability to better maintain green leaf area and high hexoses in the stem under post-flowering drought could be an osmoregulation mechanism to adapt to drought. Therefore, stay-green is an important trait to consider for sweet sorghum breeding and particularly in the objective of developing dual purpose varieties in drought prone environments.

Sorghum K 12(TKSV 0809) - A high yielding dual purpose sorghum variety for southern district of Tamil Nadu

Sorghum K 12 (TKSV 0809) is a high yielding dual-purpose sorghum variety identified for winter rainfed vertisol tracts of southern districts of Tamil Nadu. TKSV 0809 is a hybrid derivative of the cross SPV 772 x S 35-29 and evolved with an objective of development of high yielding dual-purpose short duration sorghum variety suitable for winter rainfed vertisol tracts of Tamil Nadu. TKSV 0809 was released as Sorghum K 12 variety to replace the existing variety K 8 during 2015 from Agricultural Research Station, Kovilpatti. K 12 sorghum is a short duration variety which matures in 95-100 days. K 12 sorghum is a photo insensitive variety suitable for growing in all seasons of Tamil Nadu against the ruling variety K8 which is photosensitive and suitable for Kharif season only. It recorded an average grain yield of 3123 kg/ha under the rainfed condition which is 22.4 and 23.9 per cent increased over the check K 8 and CSV 17 respectively. The K 12 Sorghum exhibited a potential grain yield of 5801 kg/ha under summer irrigated condition which is 139.3 per cent increased yield over check variety K 8.&nbsp; K 12 sorghum (TKSV 0809) is a dual-purpose variety with an average dry fodder yield of 11.9 tonnes /ha. The dry fodder yield was 31.8% increased yield over local check K 8 and 40.7% over zonal check CSV 17. The grains are creamy white in colour and suitable for cooking, popping, flaking and other value-added products. It is moderately resistant to shoot fly, stem borer and resistant to downy mildew.

β-Glucan Degradation During Malting of Different Purpose Barley Varieties

The aim of this study was to investigate the possibility of predicting the concentration of β-glucan from starting barley and malt, as well as malt and wort for different types and purpose of barley groups. The strength of the correlation between types and purpose of barley groups was determined between the values of β-glucans and other indicators of cytolytic degradation. Statistically significant correlations were obtained for β-glucans in barley-malt (r = 0.9717) and barley-wort (r = 0.9998) for brewing (B w-tr) and brewing/feed winter two-row (B/Fe w-tr) varieties, and for brewing/brewing feed/feed spring varieties (B/B-Fe/Fe w-tr) between barley and Δm (Δm = β-glucan difference between barley and malt) (r = 0.8779). For the dual-purpose varieties (B/Fe w-tr), a strong correlation for β-glucans was found between malt and wort (r = 0.8188), malt and Δm* (Δm* = % of degraded β-glucan in malt in regard to the starting β-glucan in barley) (r = −0.9099), as well as Δm and Δm* (r = 0.9951). The results indicate that the starting concentration of β-glucan in barley and malt can be used as predictors of their concentration in wort only in brewing and dual-purpose (brewing-feed) varieties.

Comparative analysis of oilseed and vegetable dual-purpose rapeseed varieties based on yield and economic benefits

Comparative analysis of oilseed and vegetable dual-purpose rapeseed varieties based on yield and economic benefits

Characterization of Marek's disease virus and phylogenetic analyses of meq gene from an outbreak in poultry in Meghalaya of Northeast India.

The aim of the present study was to characterize the virus from the lesions and histopathology of organs associated with mortality in Kuroiler (dual purpose variety of poultry developed and marketed by Keggfarms Pvt. Ltd, India) birds suspected of Marek's disease. Among 1047 birds from two farms of different location with 5.5 and 34% mortality, two types of lesion were observed in post mortem examination; tumors in vital organs-liver, spleen, kidney, lung and ovaries and generalized small nodular tumour in the abdominal cavity. Molecular characterization based on detection of ICP4 gene showed the presence of Marek's disease virus (MDV) from tissues and cell culture adapted isolates in Madin Darby Canine Kidney cell lines. Histopathological examination revealed multinucleated immature lymphoid cells infiltration in the organs. Phylogenetic analysis of the isolates based on meq gene showed the isolates belongs to cluster I genotype of MDV. This is for the first time the MDV virus is characterized from an outbreak in the poultry flock in farmer's field affecting production in Meghalaya state of North east India.

English

Sweet sorghum is considered one of the best sources of bioethanol due to its higher total reducing sugar content, which ferments completely to produce ethanol coupled with its adaptation to the changing climate. A study was carried out in Ethiopia, during the 2015/16 crop season, to determine the extent of phenotypic and genotypic relationships among 13 agronomic traits and six quality components of 28 sweet sorghum genotypes. Panicle weight and width, dry matter yield, thousand kernel weight and harvest index had significant positive correlation with grain yield and exerted favourable direct effects both at phenotypic and genotypic levels. Ethanol yield was also correlated with juice yield, sugar yield and fresh stalk yield. Therefore, these yield and quality components are suggested to receive due attention during sweet sorghum varietal selection. Moreover, days to maturity had negative correlation and imposed negative direct effect on grain yield, which may indicate the possibility to select high yielding, early maturing dual purpose varieties for dry environments where terminal drought is rampant. The studied genotypes were grouped into three clusters according to their D2 values, worthy of future breeding work considering the special merits in each cluster depending on the objectives of the breeding program. Some of the genotypes excelled as one of the two commercial sugarcane varieties used as controls for some quality traits. Therefore, considering their less water requirement, faster production cycle, and additional advantage of grain production over sugarcane, sweet sorghum stalks can serve as alternatives to sugarcane for use as feedstock in drier areas of the world under the changing climate. Key words: Bioethanol, correlation, juice, path-coefficient, sweet sorghum.

Dry Hopping with the Dual-Purpose Varieties Amarillo, Citra, Hallertau Blanc, Mosaic, and Sorachi Ace: Minor Contribution of Hop Terpenol Glucosides to Beer Flavors

The dual-purpose hop varieties Amarillo, Citra, Hallertau Blanc, Mosaic, and Sorachi Ace were recently shown to contain unusually high amounts of some discriminating terpenoids, polyfunctional thiols, and precursors of the latter (cysteine and glutathione adducts). The present work aimed to investigate the terpenol glucoside fraction in hops and its potential contribution to beer after a dry hopping process. Terpenols were quantified by stir-bar sorptive extraction GC-MS in five pilot monovarietal dry-hopped beers. In all of them, linalool and geraniol were found above their sensory thresholds (72–178 and 7–57 μg/L, respectively, for a threshold of 8 μg/L for linalool and 4 μg/L for geraniol). β-Citronellol also exceeded its threshold when the Amarillo, Citra, or Sorachi Ace cultivars were used. The hop glucoside potential was analyzed by GC-MS after enzymatic degradation. A relative hydrolysis efficiency factor was applied to our data to take into account that the commercial β-glucosidase releases octan-1-ol, used here as an internal standard, 2.8 times more efficiently than geraniol. β-Glucosidase treatment caused the release of linalool, α-terpineol, β-citronellol, and geraniol from all five dual-purpose cultivars, but in much lower amounts than the corresponding free terpenols (0.6–28.6 mg/kg of aglycons versus 7.8–109.2 mg/kg of free forms). Further quantitative analyses focusing on more traditional aromatic and bitter hops are now needed to compare their glucoside fractions with those here investigated.

Phenotypic diversity analysis of sweetpotato for breeding dual-purpose varieties

ABSTRACTThe genetic diversity available in sweetpotato has not been explored to develop dual-purpose sweetpotato varieties (DPSVs). The objectives of this study were to assess the level of phenotypic diversity present among sweetpotato varieties grown in Rwanda, and to select suitable parents for breeding DPSVs. Fifty-one diverse sweetpotato genotypes were evaluated in field trials conducted at the Rubona and Karama experimental stations of the Rwanda Agriculture Board using a 6 × 9 unbalanced alpha lattice design with three replications. Genotypes and sites showed significant interaction (P < .05), indicating differential response of genotypes in fresh root yield (FRY), root dry matter content, dry root yield (DRY), marketable root number, marketable root weight, flowering frequency and harvest index. The top two genotypes selected for their high FRY were RW11-4923 (20.9 t ha−1) and RW11-2419 (20.18 t ha−1). RW11-4923 and Wagabolige were the best performers for vine yield, producing 23.67 and 23.45 t ha−1 of vines, respectively. Ukerewe performed well for its DRY (7.09 t ha−1), while RW11-4923 had the highest mean dry vine yield (5.17 t ha−1). RW11-2910 and 8-1038 had root-to-vine ratios of 2.0 and 1.5, respectively, suggesting their suitability as breeding parents, to breed DPSVs. Two main phenotypic groups with 10 sub-groups were detected through cluster analysis. Principal component analysis showed that the first four components accounted for 76.33% of the phenotypic variation present among the 51 genotypes. The selected sweetpotato genotypes that had a combination of high storage root yields and heavy vine production should be used as parents in developing DPSVs, concurrently incorporating farmer-preferred traits.

Impacts of exposure and access to seed on the adoption of dual-purpose Cowpea and Groundnut varieties in Ghana

Dual-purpose cowpea (DPC) and dual-purpose groundnut (DPG) varieties provide good yields, improved soil fertility through nitrogen fixation, and, at the same time, provide large amounts of good quality fodder to be used as feed or manure in crop-livestock integrated farming systems in Ghana. Hence, these varieties play a significant role in improving the productivity and efficiency of crop-livestock systems in Ghana. This paper estimates the population potential adoption rates of the DPC and DPG varieties and their determinants among integrated crop-livestock farmers in Ghana when there is full access to complete and accurate information and access to the seed by farmers. Because these varieties have been newly introduced, not all farmers are aware of them nor have access to the seed. Using cross-sectional data from 608 farmers, this paper applies the average-treatment-effect method to estimate the population potential adoption rates of the DPC and DPG varieties and coefficients of their determinants among integrated crop-livestock farmers. The result shows that, potential population adoption rates of DPC and DPG could reach 78% and 85%, if all farmers have knowledge about the varieties, and up to 83% and 94%, respectively, if all the farmers have knowledge and access to seed. These results indicate that there are adoption gaps of 42% and 47% due to incomplete knowledge of DPC and DPG and 47% and 55% due to incomplete access to seed of the respective varieties. The adoption gaps suggest that there is still potential for increasing the adoption rates of these dual purpose legumes among crop-livestock farmers in Ghana if exposure and access to seed of the varieties are universal among the farmers. Also farmers with access to extension, research institutes and credit are more likely to be exposed, have access to the seed and adopt the varieties.

Redefining Agricultural Residues as Bioenergy Feedstocks.

The use of plant biomass is a sustainable alternative to the reduction of CO2 emissions. Agricultural residues are interesting bioenergy feedstocks because they do not compete with food and add extra value to the crop, which might help to manage these residues in many regions. Breeding crops for dual production of food and bioenergy has been reported previously, but the ideal plant features are different when lignocellulosic residues are burnt for heat or electricity, or fermented for biofuel production. Stover moisture is one of the most important traits in the management of agricultural waste for bioenergy production which can be modified by genetic improvement. A delayed leaf senescence or the stay-green characteristic contributes to higher grain and biomass yield in standard, low nutrient, and drought-prone environments. In addition, the stay-green trait could be favorable for the development of dual purpose varieties because this trait could be associated with a reduction in biomass losses and lodging. On the other hand, the stay-green trait could be detrimental for the management of agricultural waste if it is associated with higher stover moisture at harvest, although this hypothesis has been insufficiently tested. In this paper, a review of traits relevant to the development of dual purpose varieties is presented with particular emphasis on stover moisture and stay-green, because less attention has been paid to these important traits in the literature. The possibility of developing new varieties for combined production is discussed from a breeding perspective.

Extent of genotypic variation for maize cell wall bioconversion traits across environments and among hybrid combinations

AbstractThe utilization of maize stover as a substrate for bioenergy production demands the development of dual-purpose hybrid varieties combining both, optimal grain yield and improved biomass processing amenability. In this study, our objectives were to assess how contrasting environments influence the expression of cell wall composition and bioconversion traits relevant to cellulosic fuel production, and to study how these traits are inherited in hybrid combinations. To this end, a panel of maize double haploid (DH) lines and their corresponding test-cross (TC) offspring were tested under different locations (primarily in the Netherlands) and characterized for a variety of cell wall compositional and bioconversion features relevant to cellulosic fuel production. Overall, the DH and TC sets displayed extensive genotypic diversity in cell wall composition, polymeric ultrastructure and bioconversion characteristics. Heritability for the different traits was generally high (h2 &gt; ~0.60); essentially implying that systematic differences between genotypes remained constant across divergent environmental conditions. Moreover, correlations between the performance of DH lines and related TC hybrids were significant and favorable for most investigated traits. Strong associations (r &gt; ~0.50) were especially prominent for cell wall lignin content, degree of substitution of cell wall glucuronoarabinoxylans and cell wall convertibility following pretreatment and enzymatic hydrolysis. In conclusion, complex cell wall bioconversion traits constitute accessible and reliable selection criteria for incorporation in modern breeding programs seeking to advance bio-based maize hybrid varieties. The high heritability and environmental stability of these traits guarantee high selection efficacy during the development of superior DH/inbred material; and their predominantly additive nature prescribe that preliminary selection at the inbred level will guarantee similar correlated genetic gains in hybrid breeding.

Agronomic and qualitative evaluation of some olive selections derived from a breeding program

A breeding olive program has been established in 1994 at Egypt by crossing between local and foreign cultivars for selection and evaluation to get new genotypes for table, oil, or dual purpose varieties. Future work is planned to evaluate the adaptation of the most promising selection to different environments. During three successive years (2011-2013) progenies from crosses between cvs. (Leccio x Toffahi), (Coratina x Toffahi), (Toffahi x Arbiquine) and (Arbiquine x Toffahi) were evaluated. The progenies have been analyzed for some tree growth traits (shoot length, shoot thickness, number of nodes/shoot, internodes length, leaf traits (average number of leaves/shoot, leaf surface area, leaf shape), flowering-entity (flowering time, the length of inflorescence, number of total flowers/ inflorescence, number of perfect flowers/inflorescence, number of staminate flowers/ inflorescence, sex ratio, and fruit set/m), drupe traits (tree yield, fruit shape, fruit weight, seed weight, flesh weight, flesh/seed, moisture and oil content (oil percent in fresh weight and oil percent in dry weight) and rooting capability. From the obtained data, it can be concluded that some valuable selections have been resulted. Such progenies were No. 51, 62, and 63 for table olive; progenies No 36, 49, 109 and 121 for oil and No. 34, 35, 108, 110 and 111 for dual purpose. Furthermore, selected progenies were propagated and planted in three locations, to evaluate their performance in different geographical areas. Performance included i.e., tree growth, yield, fruit characteristics, oil content and oil compositions in fatty acids. There comes the necessity to study quantities and qualitative traits of olive production for the most important selections.

How kenaf (Hibiscus cannabinus L.) can achieve high yields in Europe and China

Kenaf is an annual spring fibre crop and it is considered as a valuable multipurpose crop due to numerous end uses. Currently, in the framework of an EU project entitled FIBRA (www.fibrafp7.net), kenaf is being investigated in Europe and China as source for sustainable bio-based products. Like all the other cultivated crops, the determination of the appropriate crop management (varieties, sowing dates, plant populations, irrigation, fertilization, weed control and harvesting time) is a key factor for the successful insertion of the crop in the existing agricultural cropping systems with economic benefits. Recently, new kenaf varieties have been released in both USA and China with increased biomass productivity and for some of them with an increased resistance to nematodes and anthracnose. Kenaf sowing should take place in spring as soon as the soil temperature is higher than 15°C. When the crop it is cultivated for its fibre stem the plant population should vary from 200,000 to 500,000plants/ha and the row spacing from 35 to 50cm. In areas that the precipitation is limited, during the hot summer months, irrigation is needed in order the crop to reach high biomass yields. It is a crop with sensitivity to nematodes, especially when it is cultivated in areas with sandy soil and this sensitivity should be taken under consideration in the rotation systems that will be applied. Harvesting time and methods should be adjusted according to the use of the crop (fibre, seeds, fibre and seeds, forage). The development of varieties or hybrids with higher yields (either for stem production or dual purpose varieties for stems and seeds production) and improved resistance to drought as well as to nematodes and anthracnose is considered one of the main challenges for the future of the crop.

Nutritional evaluation of dual purpose barley as fodder

The present study was taken up to assess the effect of N scheduling on the fodder and grain yield and on the nutritional worth of green fodder obtained from grain (RD–2552) and dual purpose (RD-2035) barley (Hordeum vulgare L.) varieties. The crop of both the cultivars was harvested 55 days after sowing (DAS) and was used as fodder. Nitrogen fertilizer (urea) was applied @ 87q/ha, either 50% at the time of sowing and 50% after 55 DAS (T1); 50% at the time of sowing, 25% after 55 DAS and 25% after next irrigation i.e. 80 DAS (T2); 33% at the time of sowing, 33% after 55 DAS and 33% after 80 DAS (T3); 33% at the time of sowing and 67% after 55 DAS (T4) or 67% at the time of sowing and 33% after 55 DAS (T5). Both the varieties of barley were cultivated in 1.15 m × 7.0 m plots in triplicate at the Ludhiana campus of Punjab Agricultural University for 2 consecutive years. The data were analyzed statistically by using 2 × 5 factorial design. The dual purpose variety, irrespective of N-scheduling, gave significantly higher fodder and significantly lower grain yield as compared to grain variety. The N-scheduling, irrespective of the genotype, did not have any significant effect on the fodder yield in 2008–09, but during 2009– 10 significantly higher fodder yield was observed in T5 as compared to T3 and T4 N- scheduling. While reverse trend was observed in grain yield i.e. it was highest in T4 followed by T3, but lowest in T1 N-scheduling in both the years of cultivation. The grain variety had significantly higher total ash, CP and hemicellulose content, while the dual purpose variety had significantly higher ADF and cellulose content. The T2 N-scheduling resulted in the highest CP and EE content and lowest cell wall constituents. The net gas production, digestibility of nutrients, VFA production and ME availability were significantly higher in the fodder of grain variety as compared to dual purpose barley variety. The N-scheduling showed no significant effect on above parameters. It was concluded that grain variety (RD-2552) had high grain and straw yield but low green fodder yield with better nutritional quality as compared to dual purpose barley variety (RD-2035).

Molecular diversity analysis in selected fodder and dual purpose oat (Avena sativa L.) genotypes by using random amplified polymorphic DNA (RAPD)

Genetic variability among 15 oat genotypes comprising fodder and dual purpose oat varieties from different geographical regions was analyzed by random amplified polymorphic DNA (RAPD) marker method in Department of Genetics and Plant Breeding, College of Agriculture, Pant University of Agriculture and Technology (G.B.P.U.A. & T.), Pantnagar. The results show appreciably high genetic diversity among the oat genotypes studied. Fifteen (15) primers selected from 20 RAPD primers could amplify 259 clear and identifiable bands, of which 250 bands were polymorphic, accounting for 96.52% genetic polymorphism. All the oat genotypes studied could be distinctly divided into two major groups with the genetic distance level at 0.46 by cluster analysis based on the Jaccard’s coefficient of similarity. The cluster break indicated sufficient genetic variability among the genotypes. Clustering pattern of the varieties appeared such that it can be grouped in the genotypes suitable for the fodder purpose and the dual purpose varieties separately. Several polymorphic bands were also found in different genotypes which helped in molecular diversity analysis of these genotypes. The results found are encouraging and indicate that RAPD technique is an easy, quick and reliable technique used for molecular diversity analysis for preliminary selection. Keywords : Oats, RAPD, genetic diversity, polymorphism. African Journal of Biotechnology Vol. 12(22), pp. 3425-3429

Identifying recommendation domains for targeting dual-purpose maize-based interventions in crop-livestock systems in East Africa

In the three major maize producing countries in the East African region of Kenya, Tanzania and Ethiopia, up to 44% of the dietary calorie requirements is provided by maize. It is also recognized that livestock are an essential asset of poor farmers in the mixed crop-livestock systems in this region. One of the major constraints to their productivity is, however, feed availability. A significant proportion of this feed is sourced from maize stover. We engaged in a multi-disciplinary research of dual-purpose maize cultivars with the purpose of contributing to smallholder food security. The specific objective of our endeavor is to better match new maize cultivars to farmers’ needs by including fodder traits in maize improvement programs in Ethiopia, Tanzania and Kenya.We explored a novel approach for targeting maize breeding research. Agricultural development strategies must recognize heterogeneity in bio-physical, economic, socio-cultural, institutional and environmental factors when devising interventions and investments. The research effort into maize as a food and feed resource was, therefore, carried out in a cross-section of bio-physically and socio-economically contrasting areas across the three study countries. To this effect the International Maize and Wheat Improvement Centre's traditional targeting framework, maize mega-environments (MMEs), was combined with recommendation domains for dual-purpose maize using a Geographical Information System (GIS). The GIS-based approach provided a spatial framework for the structured exploration of opportunities to transfer knowledge and technologies. Results show that maize is potentially an important feed resource in areas with high feed demand. Throughout the different MMEs, a range of different incentives for dual-purpose varieties can be found. The maps with recommendation domains for dual-purpose maize will facilitate better targeting of new maize cultivars. Cultivars with good quality stover can now be preferentially promoted in areas with high demand for stover as feed, while at the same time matched to the bio-physically most suitable mega-environment. This integrated approach is widely applicable and will help increase the impacts from agricultural research.

Agronomic performance of improved Cowpea varieties under natural infestation with Alectra vogelii (benth.) in the northern guinea savannah of Nigeria

Field trials were conducted over three years at Samaru in the northern Guinea savannah ecological zone of Nigeria to evaluate the performance of 20 improved cowpea varieties under conditions of natural infestation by a parasitic weed, Alectra vogelii (Benth.). Grain yield ranged from 695 to 2043 kg ha-1.The best yielding varieties were IT95K-1072-57 and IT97K-499-35. These varieties also hosted very low number of Alectra shoots, suggesting that they are resistant to it. In addition to high grain yield, both varieties produced high fodder yield, making them to be dual purpose varieties. They are therefore ideal for the semi-arid zone where livestock production is an integral part of the farming system and Alectra is a major constraint to the attainment of high cowpea yield. Alectra did not emerge on two of the varieties (IT95K-1090-12 and IT97K-818-35), indicating that they are highly resistant to the weed, but these varieties were among the poorest yielders. They may, however, be good sources of Alectra resistance in cowpea breeding programmes. Four varieties, IT95K-1380, IT93K-273-2-1, IT95K-222-5 and IT93K-573-5 supported high number of Alectra shoots and were therefore highly susceptible to its parasitism.

Turning Maize Cobs into a Valuable Feedstock

With rising energy demand and limited resources, the need for alternative energy production is increasing. Maize cobs have an advantageous composition for the production of biofuels such as cellulosic ethanol but are currently left unused on the fields after harvest. Furthermore, cobs contain a low concentration of nitrogen (<1%). Therefore, cob harvest will not deplete soil fertility. Consequently, maize cobs are a cheap and promising source for sustainable energy production. Yet with primary focus on grain yield, no or little effort has been spent to increase cob biomass yield in addition to grain yield. Both cob and grain yield are complex inherited traits affected by the environment. Breeding of dual-purpose maize varieties with simultaneously increased cob and grain yield requires a deeper understanding of factors influencing both cob and grain development. In this article, the available knowledge on the genetics of cob formation and current and future applications of maize cob utilization are discussed to evaluate the prospects for development of dual-purpose maize varieties.

Development of sorghum for bio-energy: A view from the stakeholders and priorities for breeding dual purpose varieties

Dual-purpose sorghum for both grain and bio-ethanol would be preferred to maize and sugarcane for energy production amid concerns for food insecurity and drought in southern Africa. Currently, such varieties are not available and stakeholder requirements have not been determined. Therefore, the views of stakeholders from the smallholder farming sector, industry and the academia were solicited as a first step towards setting the agenda for breeding dual purpose cultivars. Both formal and informal surveys were conducted in marginal areas in Zimbabwe, while the non-farmer stakeholders were interviewed in Zimbabwe and South Africa. It was derived that small-scale farmers have limited knowledge of bio-ethanol production, especially from sorghum stalks. However, the non-farmer stakeholders were aware and largely optimistic of the technology, an observation attributable to better access to information and experience from the sugarcane industry. All stakeholders acknowledged the potential benefits of dual-purpose sorghums in marginal environments with farmers willing to adopt them, and with encouraging views from the other stakeholders, that current sugarcane processing plants can be adjusted to handle sorghum stalks. Nonetheless, it was also perceived that adequate production could be hampered by seasonal supply of stalks because sorghum is a summer crop, and low grain productivity of current varieties ranging between 0.5 and 1.3 t ha-1. This is further compounded by unavailability of farmers’-preferred cultivars. The study indicated that, among other traits, farmers’ “ideal” variety should combine high grain yield potential with early to intermediate maturity and high stem sugar content. Unfortunately, these traits are believed to be negatively correlated or mutually exclusive such that improvement of one trait would compromise another. In addition to challenges of product design, improvement of rural infrastructure and access to capital by farmers is crucial for effective exploitation of dual purpose sorghum varieties to provide sufficient food and bio-energy. Above all, stakeholders concurred that successful implementation of the dual purpose sorghum technology would impact positively on food security, environment and rural economies. Key words: Bio-ethanol, dual-purpose sorghum, grain, stakeholder survey, stem sugar.