Genotype × environment interaction and selection for drought adaptation in sweetpotato (Ipomoea batatas [L.] Lam.) in Mozambique

Abstract

Sweetpotato is grown throughout the year in Mozambique but drought affects storage root yield and biomass productivity. The objectives of this research were to estimate the impact of genotype 9 environment interactions (G 9 E) in sweetpotato and select genotypes based on drought indices such as geometric mean, percent yield reduction, drought sensitivity index and harvest index. A total of 58 clones were evaluated during the dry season of 2006, 2008 and 2009. Two treatments were applied for this multi-year trial: full irrigation and without irrigation at the middle of root initiation growth stage. The field layout was a randomized complete block design with three replications. 'Jonathan', 'Resisto' and 'Tanzania' were the check cultivars in each treatment. Storage root and vine yields were recorded at harvest in the trials. Harvest index was computed from the yield data. The analysis of variance, regression and the additive main effects multiplicative interaction (AMMI) analyses, plus phenotypic coefficient of variation and ecovalence were used for dissecting the G 9 E and assessing the stability of each clone. Treatment, genotype 9 treatment and genotype 9 year (G 9 Y) interactions had highest contributions to the variation in storage root yield observed among clones. The stability of harvest index was significantly correlated with the absolute AMMI's IPCA1 and IPCA2 values for storage root yield. Cultivar performance varied within treatments. Four clones had significantly higher storage root yield (t ha -1 ) than 'Tanzania', the best check cultivar under drought. In conclusion, storage root yield (t ha -1 ) was negatively affected by drought and G 9 Y interaction. Harvest index stability and the geometric mean may be key to identify clones with storage root yield stability and high storage root yield under both treatments. At least two environments should be used at early breeding stages to consider harvest index in the early breeding cycle.

Physiological, Morphological Changes and Storage Root Yield of Sweetpotato [Ipomoea batatas (L.) Lam.] under PEG-Induced Water Stress

“…This lead to growth reduction in sweetpotato which was identified by low number of leaf, reduced leaf area and retarded vine length which resulted in delayed storage root formation and storage root yield reduction (Gajanayake et al, 2013(Gajanayake et al, , 2014. Screening drought tolerant trait in sweetpotato in the field trial of arid regions has been evaluated using storage root yield as major criteria (Laurie et al, 2013;Maquia et al, 2013;Kivuva et al, 2015;Andrade et al, 2016). The field trial evaluation is performed at least two crop cycles to collect the data following validated recommendation before release of the candidate varieties to the farmers.…”

“…China and United States of America (USA) has been bench-marked as 21.0 and 22.5 tons ha -1 , respectively (Mukhopadhyay et al, 2011). In contrast, the productivity of sweetpotato in African countries such as Uganda, Nigeria, Tanzania, Angola, Burundi, Mozambique, Madaguscar, Rwanda, Ethiopia, Kenya and Cameroon is very low (<10 tons ha -1 ), and hence improvement in the yield traits of sweetpotato is of prime importance to plant breeders (Tekalign, 2007;Placide et al, 2013;Andrade et al, 2016).…”

Performance of informal market sweet potato cultivars in on-farm trials in South Africa

“…A mean total storage root yield of 15.3 t/ha was observed for 10 sweet potato cultivars evaluated by Tumwegamire et al (2016). In a study by Andrade et al (2016), cultivar 199062.1 achieved a total yield of 15.3 t/ha over a three-year period at Umbeluzi, Mozambique. The mean yield observed in the present study is slightly higher than the mean marketable yield of 13.5 t/ha achieved by informal market cultivars grown by four farmers in Limpopo Province in sweet potato enterprise establishment projects.…”

Adaptation of sweet potato [Ipomoea batatas) (L.) Lam] genotypes in various agro-ecological zones of Malawi

“…A better understanding of genotypes and environment interactions (GEI) is critical for any crop varieties improvement program (Singh et al, 2006;Osiru et al, 2009;Andrade et al, 2016) as it helps breeders to identify superior genotypes and their best environments (Yan and Rajcan, 2002;Thiyagu et al, 2013). GEI refers Tanzania bred, came through Kenya Semusa CIP, Nairobi to differential sensitivity of genotype performance from one environment to another (Chalwe et al, 2017).…”