Sixty Years Of Cotton Breeding In Cameroon: Interaction Between Genetic Improvement And Rainfed Cropping Conditions
Jun 16, 2019
Breeding & Genetic improvement Climate change Network coordination Network-MedMiddleEast Climate-WestCentralAfrica Breeding-WestCentralAfrica Cotton and Environmrnt
CIRAD – France
Seed cotton (Gossypium hirsutum L) yield in Northern Cameroon has been declining since the 80s despite breeding eﬀorts. We used a set of widely grown cotton cultivars released at different dates to study genetic improvement under different cropping conditions in Cameroon, and in controlled conditions. The genetic gain was estimated with a linear regression of the variety mean on its year of release (YR). Contrasts between genetic gains observed with different planting dates were estimated and tested. Our results revealed a genetic improvement on ﬁber yield of 3.3 kg ha-1 year-1 due to increased ginning out-turn. However, there was no genetic improvement on aerial biomass, harvest index or seed cotton yield. At the early stage of development, aerial and root biomass, and potential root extraction ratio of nutrients decreased with YR. So did leaf number and hairiness at the beginning of flowering. Carbon dioxide assimilation was not affected by YR. Neither were crop cycle duration and phyllochron. Although the potential of almost all fiber technological characteristics was improved under favorable water conditions, some (upper half mean length, short fiber index, uniformity index, and strength) were reduced in water-limited conditions. We concluded that cotton breeding efforts in Cameroon have successfully improved cotton fiber yield and the potential of most fiber technological characteristics. However, in water-limited conditions, fiber quality tended to decrease with the YR. There is still some room for seed cotton yield improvement.
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