Development and evaluation of new sweetpotato varieties through farmer participatory breeding for high altitudes in Kenya.

Abstract

Sweetpotato (Ipomoea batatas L.) plays a significant role in food and nutritional security in Kenya. However, production is constrained by: (i) Sweet potato virus diseases (SPVD) and weevils (Cylas spp.); (ii) shortage of clean planting materials; (iii) lack of suitable varieties for high altitude agroecosystems; (iv) poor postharvest handling; and (v) poor market access. In order to enhance the role of sweetpotato for food security, a breeding programme was initiated at Kenya Agricultural Research Institute (KARI)-Njoro with the objective of developing varieties with desirable genetic and agronomic attributes which include high yields, resistance to SPVD and weevils, improved food quality, and market acceptability for high altitudes. Thirty-six potential parents were identified in initial screening of 440 accessions from landraces, improved and imported accessions. Hand and polycrossing process was performed to generate a breeding nursery of 2200 seedlings. Forty-three entries were identified for advancement to preliminary yield evaluation. Out of these, ten entries were advanced to multi-location testing in five sites under the oversight of the National Performance Trials committee. The multi-location trials were conducted on a randomized complete block design with three replicates at Kabianga (LH1-1745 m above sea level (masl)), Ravine (LH3-2167 masl), KARI-Lanet (LH4-1920 masl), Lare (LH4-1900 masl) and KARI-Njoro (LH3-2166 masl). The sites were in the Central Rift Valley region. Participatory variety evaluation by researchers, extensionists, plant regulators and farmers was adopted in all the trials. Standard operating procedures and analyses as prescribed by the International Potato Center and the Kenya Plant Health Inspectorate Service were used to evaluate: (i) yields; (ii) viruses and weevils; (iii) dry matter content; (iv) beta-carotene; and (v) acceptability by consumers. The main result of the trials' evaluation was the release of five new varieties - three orange-fleshed Kenspot-4, Kenspot-5 and Kenspot-3; yellow-fleshed Kenspot-1; and white-fleshed Kenspot-2. The improved varieties have better average root yields (20 t/ha) compared with the national average root yields (12.8 t/ha); moderate field resistance to SPVD and weevils; moderate dry matter content (26-32%); and consumer acceptability. The orange-fleshed sweetpotato varieties will provide consumers and farmers with moderate provitamin A contents which will alleviate vitamin A deficiency in Kenya. Through participatory breeding, production capacity of sweetpotato at high altitudes has increased providing food security, farmer adoption knowledge has improved, market strategies have been determined and food quality has improved. Variety recommendation is agroecological specific.

Orange‐fleshed sweetpotato production: Progress and perspectives for value chain development in West Africa

“…20,21 The improved varieties generally came from farmers landraces [70][71][72][73][74] ; imported cultivars 46,51,75 ; and bred cultivars. 31,47,76,77…”

“…The importance of improving the availability of adapted OFSP varieties was mentioned during the period of OFSP potential recognition in East Africa 20,21 . The improved varieties generally came from farmers landraces 70–74 ; imported cultivars 46,51,75 ; and bred cultivars 31,47,76,77 . Since the introduced varieties and local landraces presented some non‐preferred traits by stakeholders in OFSP value chains, it is important to initiate some breeding efforts to improve agronomic and culinary traits, and combined desired traits in one genotype.…”

Morphological Variability and Storage Root Productivity of Some Sweet Potato (Ipomoea Batatas (L.) Lam) Genotypes in An Ultisol

“…Estimated yields of sweet potato among small holders' farmers in Nigeria are comparatively minimal, 2.6t/ha compared with average sweet potato yield in Africa (9.6t/ha) and the world's yield average (15.9t/ha). This lowering trend could be attributed to a number of factors, including inappropriate agronomic practices and prolonged usage of local accessions with diminishing yield potentials and limited circulation of the improved varieties (Karanja et al, 2013).…”