Development of interspecific hybrids between three American yam bean species (Pachyrhizus spp.).

American yam bean (Pachyrhizus Richard ex DC.), a neotropical legume, is cultivated in Latin America and Asia for its edible and crunchy storage roots. Because of their low dry matter content and 'fruity' nature, roots are usually consumed raw. In order to increase root dry matter content and promote a wider use of American yam beans for food and starch processing interspecific crosses were made between P. tuberosus (Chuin) germplasm originating from the Peruvian Amazon and two other domesticated yam bean species: P. ahipa native to the Andean highlands and P. erosus originating from Central America. While the 'Chuin' type is characterized by high storage root dry matter content, P. erosus is high yielding and drought tolerant and P. ahipa performs well in high altitudes. The breeding experiment was designed as a completely diallelic cross between three P.ahipa and three P. tuberosus accessions and between three P. erosus und three P. tuberosus accessions. Nine P. ahipa x P. tuberosus (Chuin) F1 cross populations as well as 9 P. erosus x P. tuberosus (Chuin) F1 cross populations were developed. Hybridity of interspecific progenies was confirmed by morphological and agronomical evaluation and multivariate statistical analysis. Hybrid plants were generally fertile and vigorous. The resulting 18 F1 interspecific and 12 F1 intraspecific cross populations are used to generate a large number of F2 lines that serve to select genotypes with high dry matter and high starch content as well as good adaptation to a broad range of environmental conditions

Contenido de beta-caroteno, hierro y zinc, efecto de almacenamiento y tipo de cocción en genotipos de camote (Ipomoea batatas L)

El camote (Ipomoea batatas L) es el principal componente en la dieta de millones de personas que viven en países tropicales, y un mejoramiento en el contenido de â-caroteno podría incrementar el suministro de vitamina A para satisfacer la mayor parte de las necesidades diarias de la gente. En el presente estudio, el contenido de â-caroteno (BC), hierro (Fe) y zinc (Zn) fueron determinados en 25 genotipos de camote provenientes de las localidades de La Molina y San Ramón (Perú). Así mismo, los cambios en el contenido de BC en siete genotipos de camote fueron investigados usando diferentes métodos de cocción y tiempos de almacenamiento. El contenido de BC fue medido vía absorbancia a 450 nm e identificado a través del HPLC y el contenido de Fe y Zn fueron determinados a través de técnicas de ICP-OES. Los resultados muestran variación significativa entre genotipo, ambiente y en la interacción genotipo-ambiente. La concentración de BC en las raíces de camote recién cosechado varió entre 7.62 y 18.93 mg/100 g en peso fresco (PF). El contenido de hierro presentó un rango de 0.40 – 0.96 mg/100 g PF y el contenido de zinc presentó un rango de 0.25 – 0.51 mg/100 mg PF. Los genotipos 440442 y 440518 presentaron los niveles más altos de BC en los dos ambientes. Diferencias en el contenido de BC fueron encontrados entre los métodos de cocción y los tiempos de almacenamiento. La concentración de BC de las raíces cocidas por ebullición (15.15 mg/100 g PF) fue mayor que las raíces cocidas por horneado (14.29 mg/100 g PF); sin embargo, no hubo diferencias entre los genotipos 440442 y 420081 por efecto del método de cocción. Asimismo, el contenido de BC se incrementó durante el tiempo de almacenamiento, donde el genotipo 440442 presentó los mayores niveles de BC durante el tiempo de almacenamiento, mientras que los genotipos 440413 y 440513 no presentaron cambios significativos

Breeding in Africa for Africa

Traditionally, sweetpotato breeding programs have taken a long time, 7 to 8 years, to produce a new variety. Moreover, as of 2008, most countries in Africa had no real breeding program and relied on testing materials developed elsewhere. This flyer explains the work done by 13 active breeding programs in SSA between June 2014 and July 2015 to strengthen conventional sweetpotato breeding, develop accelerated breeding protocols and invest in breeding diverse sweetpotato types to meet the requirements of a wider range of producers and consumers

Genotype x environment interactions for a diverse set of sweetpotato clones evaluation across drought prone environment of Mozambique.

Sweetpotato is grown during the rainyand during the dry season in Mozambique (the rainy season is very unstable). In total 58 clones were evaluated across three years during the dry season and with two treatments (with and without irrigation during the initial growing stages). Three check clones were used (Jonathan, Resisto, and Tanzania). The G x E analysis was conducted by ANOVA, regression, and AMMI analysis. Ratios of variance components due to genotypes, genotype x year, genotype x treatment, genotype x year x treatment, and the plot error were 1: 2.90:0.52:1.27: 3.98 for storage root yield and 1:0.45:0.13:0.29: 1.45 for upper biomass yield – corresponding heritabilities were 37.6 and 74.5, respectively. The stability of harvest index was significantly correlated with the PCA1 and PCA2 values obtained from AMMII analysis with storage root yields. Fifteen clones were found to have higher storage root yields compared to the best check (Resisto) with initial irrigation, whereas only four clones were found to have higher storage root yields compared to the best check (Tanzania) without initial irrigation. AMMI analysis revealed a group of genotypes with high additive main effects and PCA1 values close to zero for storage root yield. Moreover, a multiplicative index was tested to facilitate selection. In conclusion, storage root yield genotype by year; it can be extreme under drought prone growing conditions of sweetpotato. This makes right selection decisions and breeding progress difficult. Harvest index stability might be a key trait to identify clones with yield stability under drought prone growing conditions. At least two environments should be used at early breeding stages to consider this trait early in the breeding process