Cassava (Manihot esculentaCrantz) is an important industrial and staple crop due to its high starch content, low input requirement, and resilience which makes it an ideal crop for sustainable agricultural systems and marginal lands in the tropics. However, the lack of genomic information on local genetic resources has impeded efficient conservation and improvement of the crop and the exploration of its full agronomic and breeding potential. This work was carried out to obtain information on population structure and extent of genetic variability among some local landraces conserved at the Plant Genetic Resources Research Institute, Ghana and exotic cassava accessions with Diversity Array Technology based SilicoDArT and SNP markers to infer how the relatedness in the genetic materials can be used to enhance germplasm curation and future breeding efforts. A total of 10521 SilicoDArT and 10808 SNP markers were used with varying polymorphic information content (PIC) values. The average PIC was 0.36 and 0.28 for the SilicoDArT and SNPs respectively. Population structure and average linkage hierarchical clustering based on SNPs revealed two distinct subpopulations and a large number of admixtures. Both DArT platforms identified 22 landraces as potential duplicates based on Gower’s genetic dissimilarity. The expected heterozygosity which defines the genetic variation within each subpopulation was 0.008 for subpop1 which were mainly landraces and 0.391 for subpop2 indicating the homogeneous and admixture nature of the two subpopulations. Further analysis upon removal of the duplicates increased the expected heterozygosity of subpop1 from 0.008 to 0.357. A mantel test indicated strong interdependence (r = 0.970; P < 0.001) between SilicoDArT and DArTSeq SNP genotypic data suggesting both marker platforms as a robust system for genomic studies in cassava. These findings provide important information for efficientex-situconservation of cassava, future heterosis breeding, and marker-assisted selection (MAS) to enhance cassava improvement.
1 December 2020 in Ecological Genetics and Genomics
Rice production in Ghana has become unsustainable due to the extremely nutrient-poor soils. It is caused by inadequate soil fertility management, including the inefficient application of fertilizers. A practical solution could be the biofertilizers, Azospirillum sp. B510. We performed field trials in Ghana and Japan to compare the effects of B510 colonization on selected Ghanaian rice varieties grown. The B510 inoculation significantly enhanced the rice cultivars’ growth and yield. The phenotypic characteristics observed in rice varieties Exbaika, Ex-Boako, AgraRice, and Amankwatia were mainly short length and high tillering capacity. These features are attributed to the host plant (cv. Nipponbare), from which the strain B510 was isolated. Furthermore, Azospirillum species has been identified as the dominant colonizing bacterium of rice rhizosphere across a diverse range of agroecologies in all major rice-growing regions in Ghana. Our results suggest that the utilization of B510 as a bio-fertilizer presents a promising way to improve rice growth, enhance soil fertility, and sustain rice productivity in Ghana.
13 March 2019 in International Journal of Agronomy
Hybrid rice technology is one of the promising, sustainable, and proven technologies for increasing rice production and productivity with a yield advantage of 15–30% over modern inbred varieties. The potential of hybrid rice has so far not been exploited in Ghana. This study was undertaken to evaluate the yield potential, reaction to diseases, and physical grain attributes of some introduced hybrids. The trials were laid out in a randomized complete block design (RCBD) with three replicates across three locations. Data were taken on grain yield, yield components, reaction to diseases, and grain physical characteristics. Four promising hybrids (SWARNA 2, ARGH 1501, ARGH 1502, and ARGH 1503) with a mean yield advantage of 15–20.8% over the best inbred check “AgraRice” were identified. With few exceptions, the hybrids were broadly adapted and had adequate resistance to blast and bacterial leaf blight. Most of the test hybrids had long slender grains which make them acceptable to the Ghanaian market but lacked aroma.
Hybrid rice varieties exploit the phenomenon of heterosis to out-yield their inbred counterpart to increase productivity per unit area. Unlike inbred rice varieties whose seeds could be used for replanting season after season, farmers will have to purchase seeds of hybrids every season to obtain the expected yield and other quality attributes. While the hybrid system is a disadvantage to farmers in terms of mandatory seed purchase, it serves as a motivation and opportunity for private seed companies to recoup their investment and therefore encourages their involvement in seed production research and development. Hybrid rice technology originated from China and is well commercialized in Asia and the Americas. Africa is among the few places where hybrid rice is still not fully commercialized. Besides Egypt, many African countries have just begun to exploit the benefits of hybrid rice technology. A number of introduced hybrids have exhibited a 15–20% yield advantage over the available top inbred varieties. Most African countries also have a conducive environment for viable hybrid rice seed production. Besides other pertinent challenges, some which can be addressed technically, there should be a recommended production package that will give farmers the best of yield to enable hybrid rice contribute to attaining rice self-sufficiency in Africa.