Early selection for yield in robusta coffee based on juvenile growth traits

Variety development, particularly for tree crops is a long-term exercise requiring significant resource investments, over many years of evaluation. Identification of traits at early growth stages that are predictive of future performance would facilitate the breeding process. The objective of this study was to assess the value of juvenile trunk cross-sectional area (TCSA) and number of laterals for selecting high-yielding Robusta coffee ( Coffea canephora ) genotypes, early in a breeding programme. Seventy-two Robusta coffee clones developed by either ortet selection, from previous progeny trials/clonal trials carried out at the Cocoa Research Institute of Ghana (CRIG), were planted in 2011 in a randomised complete-block design with five replications, at CRIG\u2019s experimental fields. Juvenile TCSA and number of laterals were effective predictors of yield. Genotypes that combined small TCSA and less number of laterals at the juvenile growth phase had the lowest cumulative yields, and vice versa. TCSA was significantly associated with yearly yields (2015: r = 0.49, P < 0.001; 2017: r = 0.35, P < 0.001) and cumulative yield (r = 0.41, P < 0.001). Similarly, a significant (P < 0.001) correlation was observed between juvenile number of laterals and yearly yields (2015: r = 0.58, 2016: r = 0.24; 2017: r = 0.48), and cumulative yield (r = 0.57, P < 0.001). A selection index that combines large juvenile TCSA and many number of laterals has the potential of identifying productive genotypes early in a Robusta coffee breeding programme.Le d\ue9veloppement des vari\ue9t\ue9s, en particulier pour les cultures arboricoles, est un exercice \ue0 long terme qui n\ue9cessite des ressources importantes investissements, au cours de nombreuses ann\ue9es d\u2019\ue9valuation. Identification des traits aux premiers stades de croissance qui sont une pr\ue9vision des performances futures faciliterait le processus de s\ue9lection. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la valeur de la section transversale du tronc juv\ue9nile (TCSA) et le nombre de travers\ue9es pour s\ue9lection de g\ue9notypes de caf\ue9 Robusta ( Coffea canephora ) \ue0 haut rendement, au d\ue9but d\u2019un programme de s\ue9lection. Soixante-douze clones de caf\ue9 Robusta ont \ue9t\ue9 mis au point soit par s\ue9lection, soit \ue0 partir d\u2019essais ant\ue9rieurs sur la descendance / essais clonaux r\ue9alis\ue9s \ue0 l\u2019Institut de recherche sur le cacao du Ghana (CRIG) ont \ue9t\ue9 plant\ue9s en 2011 dans un conception de blocs complets randomis\ue9s avec cinq r\ue9p\ue9titions, sur les champs exp\ue9rimentaux de CRIG. TCSA juv\ue9nile et le nombre de lat\ue9raux \ue9taient des pr\ue9dicteurs efficaces du rendement. Des g\ue9notypes combinant de petites TCSA et un nombre moins \ue9lev\ue9 de plantes lat\ue9rales \ue0 la phase de croissance juv\ue9nile pr\ue9sentait les rendements cumulatifs les plus bas, et inversement. Le TCSA \ue9tait associ\ue9 de mani\ue8re significative aux rendements annuels (2015: r = 0,49, P <0,001; 2017: r = 0,35, P <0,001) et rendement cumul\ue9 (r = 0,41, P <0,001). De m\ueame, une corr\ue9lation significative (P <0,001) a \ue9t\ue9 observ\ue9e entre le nombre de lat\ue9rales juv\ue9niles et les rendements annuels (2015: r = 0,58, 2016: r = 0,24; 2017: r = 0,48), et rendement cumul\ue9 (r = 0,57, P <0,001). Un index de s\ue9lection associant une grande TCSA juv\ue9nile et de nombreuses nombre de produits lat\ue9raux a le potentiel d\u2019identifier des g\ue9notypes productifs t\uf4t dans un caf\ue9 Robusta programme d\u2019\ue9levage

Assessment of Juvenile Growth and Yield Relationship Among Dwarf Cashew Types in Ghana

Cashew (Anacardium occidentale L.) is an important tropical cash crop cultivated in Ghana. It provides livelihood for about 200,000 people and contributes 6.1% to Ghana&amp;rsquo;s gross domestic product (GDP). Four Brazilian dwarf accessions were introduced to improve nut yield. Objectives of this study were to (1) assess the agronomic performance of the accessions across two contrasting ecologies, (2) determine environmental influence on juvenile growth, (3) determine the relationship between early vegetative growth and yield and (4) explore heritability and genetic advance for the measured agronomic traits. The experiment was laid out in a randomized complete block design with 3 replications. Results revealed significant (p &amp;lt; 0.05) environmental influence on growth and yield of cashew. Transitional savanna agro-ecology is more suitable for cashew growth and development. Crop year, location and crop year &amp;times; location interactions also influenced most of the agronomic traits. Early growth characteristics alone were not enough to predict yield. Genotype B2 ranked highest yielding across the agro-ecologies. Moderate to high heritability and genetic advance estimates were observed for nut yield, plant height and girth, an indication of variability among accessions needed for cashew improvement in Ghana.</jats:p

Genetic Introgression from Glycine tomentella to Soybean to Increase Seed Yield

Soybean [Glycine max (L.) Merr.] breeding in the United States currently relies on a narrow genetic base. Glycine tomentella Hayata (2n = 78), native to Australia, is a perennial relative in the tertiary gene pool of soybean. No effort has been devoted to using this species to increase seed yield. The objectives of this research were (i) to identify high-yielding lines derived from backcrosses between the soybean cultivar Dwight (2n = 40) and G. tomentella PI 441001 (2n = 78) and to compare their agronomic performance with that of the recurrent parent, and (ii) to determine associations between G. tomentella introgressions and agronomic traits. PI 441001 was crossed to Dwight and immature seed rescue was used to produce a sterile F1 plant. Amphidiploid plants (2n = 118) were produced by treating the F1 hybrid with colchicine. Amphidiploid plants were backcrossed to Dwight and a series of backcrosses were made to obtain lines with 2n = 40 chromosomes, which were self-fertile and genetically stable. Preliminary yield testing was used to select 180 lines in maturity groups II, III, and IV that had yields greater than or less than that of the recurrent parent. Yield data collected in two replication tests at six to eight locations in 2013 and 2014 identified experimental lines in all three maturity groups that were higher yielding than the recurrent parent. All experimental and parental lines were genotyped, revealing an average of 1% G. tomentella introgression. Significant associations were detected between G. tomentella introgressions and time of flowering, height, lodging, and yield