Inheritance of resistance to head bug (Eurystylus oldi) in grain sorghum (Sorghum bicolor)

The inheritance of resistance to head bug (Eurystylus oldi) was studied in ten populations of sorghum derived from crossing three susceptible sorghum elite varieties (ICSV 111, ICSV 112 and ICSV 400), and two resistant sorghum varieties (Malisor 84-7 and KSV 4). Parental lines, F1 and F2 populations were sown on a Randomized Complete Block Design in two replications. Artificial infestation of head bugs on sorghum was employed in carrying out the experiment. Samples of 5 panicles each from every artificially infested plot were observed. Resistance to head bug in sorghum seems to be controlled by a single pair of recessive genes in Malisor 84-7 x ICSV 400 and Malisor 84-7 x ICSV 111. The cross, KSV 4 x ICSV 112 appeared to be controlled by double recessive pair of genes. Head bug population affects quality of grains rather than the yield produced. There is a negative correlation (-0.095) between head bug population and the germination percentage of the grain. Positive relationship exists between glume size and head bug population, which suggests that longer glumes harbour more head bug. (African Journal of Biotechnology: 2003 2(7): 202-205

Marker Assisted Foreground Selection for Identification of Striga Resistant Backcross Lines in Sorghum bicolor

Striga is a major constraint to sorghum production causing high yield loss due to increasing infestation. Locally-adapted cultivars with resistant genes/QTLs could be an effective control strategy for Striga. Marker-Assisted Foreground Selection was used to select backcross lines possessing Striga resistance QTLs from N13. Marker polymorphism was conducted for the donor parent N13 and 10 recurrent parents using 10 Simple Sequence Repeat (SSR) markers. Recurrent parents with SSR alleles, polymorphic to the donor parent allele were selected. F1 lines were developed by making a cross between the selected recurrent parent and the donor. The F1 were confirmed for heterozygosity using SSR markers. Selected heterozygote F1s were backcrossed to their recurrent parent to develop backcross populations (BC1F1 and BC2F1). BC1F1 and BC2F1 populations were genotyped using SSR markers flanking the Striga resistant QTLs in N13. Forty two DANYANA-N13 BC2F1 lines (with 4 QTLs in 3 lines, 3 QTLs in 10 lines and other 28 lines having 1 to 2 QTLs) were selected for the presence of N13 QTLs. Forty three SAMSORG39-N13 BC2F1 lines (with 3 QTLs in 2 lines while 41 lines had 1 to 2 QTLs) were also selected for the presence of N13 QTLs. Although, selected lines will be genotyped for the recovery of recurrent parent background and evaluated to identify elite genotypes for possible release as varieties, the successful introgression of Striga resistance QTLs using Marker Assisted Selection suggests that in developing superior sorghum varieties, breeders could make use of molecular marker technologies to speed up breeding programmes

Genetic Variation for Striga hermonthica Resistance and Yield Among Sorghum Accessions in Nigeria

Striga hermonthica (Delile) Benth., commonly referred to as witch weed, is a major constraint to sorghum (Sorghum bicolor (L.) Moench) production in the Northern region of Nigeria because of high yield losses due to infestation. To identify parental lines useful in breeding for S. hermonthica resistant sorghum genotypes adapted to Nigeria, twenty-five sorghum accessions were evaluated in Nigeria across three test environments. Both phenotypic and genetic components influenced the variation observed in the sorghum accessions. The estimates for the genetic coefficient of variation, heritability and genetic advance for the area under Striga number progress curve (ASUNPC), Striga emergence counts, yield and other agronomic traits, obtained in this study revealed that genetic gain for resistance to S. hermonthica could be realized through selection. Based on the performance of the 25 sorghum accessions SRN39, Danyana, Sepon82, and SAMSORG40 were the top four accessions found to be most resistant to S. hermonthica. Assessment of resistance was based on the low Striga emergence counts and the ASUNPC values. These accessions can be used as donor sources of S. hermonthica resistant genes for introgression into cultivars adapted to Nigeria, followed by recombination breeding for pyramiding the different resistance mechanisms

Genetic diversity assessment of sorghum (Sorghum bicolor (L.) Moench) accessions using single nucleotide polymorphism markers

Sorghum (Sorghum bicolor (L.) Moench) is an important resource to the national economy and it is essential to assess the genetic diversity in existing sorghum germplasm for better conservation, utilization and crop improvement. The aim of this study was to evaluate the level of genetic diversity within and among sorghum germplasms collected from diverse institutes in Nigeria and Mali using Single Nucleotide Polymorphic markers. Genetic diversity among the germplasm was low with an average polymorphism information content value of 0.24. Analysis of Molecular Variation revealed 6%variation amonggermplasmand 94%withingermplasms.Dendrogramrevealed threegroupsof clusteringwhich indicatevariationswithinthegermplasms. Privatealleles identified inthesorghum accessions from National Center for Genetic Resources and Biotechnology, Ibadan, Nigeria and International Crop Research Institute for the Semi-Arid Tropics, Kano, Nigeria shows their prospect for sorghum improvement and discovery of new agronomic traits. The presence of private alleles and genetic variation within the germplasms indicates that the accessions are valuable resources for future breeding programs

In vitro culture of Telfairia occidentalis under different cytokinins and auxin combination

Telfairia occidentalis is a tropical vine and has been a good source of iron rich vegetable to man. It is normally propagated through seeds but the seeds are recalcitrant in nature. The vegetative propagation of T. occidentalis has been difficult hence there is a need to develop an in vitro method. Nodal cuttings of T. occidentalis was cultured on Murashige and Skoog (MS; 1962) basal media supplemented with IBA, IAA, NAA, BAP, and kinetin at different concentrations. Among all the growth hormones used, IBA and BAP combination gave the best result for both rooting and shooting while BAP in combination with NAA showed the highest number of nodes. The result showed that in vitro growth of T. occidentalis is hormone specific

Adapting Agriculture to Climate Change: A Synopsis of Coordinated National Crop Wild Relative Seed Collecting Programs across Five Continents

The Adapting Agriculture to Climate Change Project set out to improve the diversity, quantity, and accessibility of germplasm collections of crop wild relatives (CWR). Between 2013 and 2018, partners in 25 countries, heirs to the globetrotting legacy of Nikolai Vavilov, undertook seed collecting expeditions targeting CWR of 28 crops of global significance for agriculture. Here, we describe the implementation of the 25 national collecting programs and present the key results. A total of 4587 unique seed samples from at least 355 CWR taxa were collected, conserved ex situ, safety duplicated in national and international genebanks, and made available through the Multilateral System (MLS) of the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant Treaty). Collections of CWR were made for all 28 targeted crops. Potato and eggplant were the most collected genepools, although the greatest number of primary genepool collections were made for rice. Overall, alfalfa, Bambara groundnut, grass pea and wheat were the genepools for which targets were best achieved. Several of the newly collected samples have already been used in pre-breeding programs to adapt crops to future challenges.info:eu-repo/semantics/publishedVersio

Adapting agriculture to climate change: a synopsis of Coordinated National Crop Wild Relative Seed Collecting Programs across five continents.

Na publicação: Marcelo B. Medeiros

Full Length Research Paper - Inheritance of resistance to head bug (Eurystylus oldi) in grain sorghum (Sorghum bicolor)

The inheritance of resistance to head bug (Eurystylus oldi ) was studied in ten populations of sorghum derived from crossing three susceptible sorghum elite varieties (ICSV 111, ICSV 112 and ICSV 400), and two resistant sorghum varieties (Malisor 84-7 and KSV 4). Parental lines, F1 and F2 populations were sown on a Randomized Complete Block Design in two replications. Artificial infestation of head bugs on sorghum was employed in carrying out the experiment. Samples of 5 panicles each from every artificially infested plot were observed. Resistance to head bug in sorghum seems to be controlled by a single pair of recessive genes in Malisor 84-7 x ICSV 400 and Malisor 84-7 x ICSV 111. The cross, KSV 4 x ICSV 112 appeared to be controlled by double recessive pair of genes. Head bug population affects quality of grains rather than the yield produced. There is a negative correlation (-0.095) between head bug population and the germination percentage of the grain. Positive relationship exists between glume size and head bug population, which suggests that longer glumes harbour more head bug