Development Of End-User Preferred Sweetpotato Varieties In Ghana

ABSTRACT Studies were undertaken to identify the constraints to increase sweetpotato utilization in Ghana and to develop end-user preferred varieties that would increase utilization in Ghana and beyond. A survey was conducted using Focus Group Discussion (FGD) followed by administration of Semi-Structured Questionnaire. This was done in some selected communities in Ghana where sweetpotato is popular in February 2012. Sweetpotato germplasm was also collected from farmers’ field in these areas, and from National Agricultural Research Stations of Ghana as well as the International Potato Centre (CIP) research station at Fumesua, Ghana in 2010. The germplasm was evaluated at two locations in the major and minor cropping seasons in 2011 for beta-carotene, dry matter and sugar contents as well as other agronomic and quality traits. Crosses among four genotypes, two with low sugar, high dry matter, low beta-carotene contents, and the other two with high sugar, low dry matter and high beta-carotene contents, were made to determine gene action influencing these three traits and other quality traits from 2012 to 2013. Four superior genotypes with low sugar content and five with high beta-carotene content were selected as parents for the development of low sugar and high beta-carotene populations, respectively, from 2012 to 2013. The survey showed that consumers in Ghana desire non-sweet, high dry matter sweetpotatoes with low or moderate beta-carotene content. Agro-morphological and physico-chemical descriptors revealed high variation among the sweetpotato accessions and it was confirmed by the SSR markers. Much of the genetic variation identified among the sweetpotato genotypes was additive in nature. Sufficient useful genetic variation was present in the germplasm and was exploited for improvement on beta-carotene, dry matter and sugar contents. There was significant heterosis for beta-carotene, dry matter and sugar contents. Fifteen percent of the low sugar population developed had sugar content less than 12% (nonsweet staple types) whilst the remaining 85% had sugar content of 12 – 20% (low sugar). Fourteen percent of the high beta-carotene population developed were low sugar (12 – 20%) genotypes. Seven non-sweet (preferred staple types) hybrids, 30 low sugar hybrids, 16 high beta-carotene and moderate dry matter content hybrids, and 18 high yielding hybrids were identified. There is a high potential for identifying hybrids that combine all the preferred traits and so further testing needs to be done multi-locational for potential release to farmers.