Genetic incompatibilities in sweetpotato and implications for breeding end-user preferred traits

Abstract

Sweetpotatoes utilization is low in Ghana due to lack of farmer and consumer preferred cultivars. Poor flowering and incompatibilities among genotypes limit breeding progress in its improvement. The objective was to assess compatibilities among sweetpotato genotypes to select good parents for breeding end-user preferred varieties for increased utilization. Twenty-one genotypes selected from 115 accessions evaluated across three contrasting environments were crossed using full diallel mating scheme. In all, 6388 crosses were carried out and 3214 seeds produced. This study sought to understand the genetic incompatibilities based on the number of seeds set per capsule after self-or cross-fertilization. Lack of flowering or poor flowering, and self-and cross-incompatibilities were major constraints to sweetpotato improvement found. Four genotypes (Histarch, Apomuden, Beauregard, and Ogyefo) were the best parents based on cross compatibilities and they can be used to determine the genetic control of beta-carotene, dry matter and sugar content in sweetpotato. Histarch and Ogyefo are recommended as parents for the development of non-sweet, high dry matter sweetpotato varieties that are the preferred cultivars in Ghana because of their low sugar content. Use of many genotypes in hybridization and establishment of crossing blocks in the minor cropping season is highly recommended.

Crossing Among Sixteen Sweet Potato Parents for Establishing Base Populations Breeding

“…This study used diverse genotypes and making many controlled crosses to resolve cross-incompatibility in sweet potato. The results of this study are in line with the findings of Baafi et al (2016).…”

“…However, they were dominated by compatible pairs, and only a small portion was partially incompatible to fully incompatible. Some studies have shown similar results as in this study (Afolabi, Carey, & Akoroda, 2014;Baafi et al, 2016;Indriani, Ashari, Basuki, & Jusuf, 2017;Rahajeng & Rahayuningsih, 2013;Sseruwu, Shanahan, Melis, & Ssemakula, 2016).…”

“…The development to improve sweet potato varieties can be obtained in three ways, first by evaluating local germplasm collection, second by introducing cultivars, and third by developing cultivars through hybridization (Baafi et al, 2016;Mbusa et al, 2018). Establishing base population of sweet potato through hybridization in breeding program involves many sweet potato parents that have many numbers of flowers and cross-compatible nature to each other in order to produce many seeds set (Lestari, 2010;Mbusa et al, 2018;Mwanga et al, 2017).…”

“…In this case the selfsterile in question is self-incompatible. Gurmu, Hussein, & Laing (2013) also reported that sweet potato has the inherent nature of self-and crossincompatible, highly heterozygous, and a large of small chromosome number (2n = 6x = 90), make their genetic improvement complicated (Baafi et al, 2016). According to Sattler, Carvalho, & Clarindo (2016), sweet potato is a hexaploid, and the polyploid often results in reduced fertility due to meiotic errors, allowing the production of seedless varieties.…”

Analysis of micronutrients variations among sweet potato (Ipomoea batatas [L.] Lam) genotypes in Malawi

“…Acceptable levels of dry matter content in preferred genotypes in Malawi are ≥30% (Chipungu et al, 1999) and Kamchiputu and Yoyera are among the best genotypes. Genotypes with high dry matter are preferred because they are usually low in sugar (Baafi et al, 2016a). Determination of dry matter is important since % DM is among key component traits that contribute to total root yield (TRY), others being large root yield (LRY), number of large root per plant (NLR/P), root dry matter yield (RDMY) and harvest index (HI) (Amoatey et al, 2016).…”