Amuge E.S. 1, Mukasa S. 1, Gibson P. 1, Pariyo A.2 and Baguma Y.2

Grafting to enhance flowering and seed set in selected cassava varieties in Uganda

1) College of Agriculture and Environmental Sciences, School of Agriculture, Production Department, Makerere University, PO Box 7062, Kampala, Uganda, 2)National Crops Resources Research Institutes (NaCRRI) Namulonge, PO Box 7084, Kampala, Uganda. * [email protected], Registrant ID#

Cassava (Manihot esculenta Cranz), family Euphorbiaceae, is a perennial shrub and is used as food, animal feed and as a raw material for industry. Cassava improvement is limited by non-flowering or poor flowering genotypes and poor seed set. This makes it difficult for breeders to cross genotypes that have desirable traits such as a high dry matter content and tolerance to major diseases and pests. Grafting has a potential to encourage flowering in cassava genotypes with agriculturally important traits. It has successfully been used to increase flowering and seed set in sweet potato, Arabidopsis, soybean and tobacco. The aim of this study is 1) to determine a suitable grafting technique that enhances flowering and seed set in cassava, 2) To identify understock-scion genotype combinations that produce increased flowering and seed production through grafting, and 3) To establish the effect of different post-grafting pruning of scions on flowering and seed set in cassava. This study will be conducted at NaCRRI from May 2014 to May 2016 in three stages. The first stage with use grafting using whip and wedge methods to determine the grafting technique with the best frequency of success, flowering and good seed set, A completely randomized design with two replications using two genotypes (NASE14 and TME204) will be used. The second stage will determine understock-scion genotype combinations that results in good flowering and set seed when grafted. A split plot design with three replications, 16 genotypes of understocks and five genotypes for scions will be used. The third stage will establish the effect of post grafting pruning of scions on flowering and seed production using two genotypes (NASE14 and TME204) in a split plot with 4 replications. By the end of this study we expect to identify suitable grafting and pruning techniques for enhancing flowering and seed set in cassava. We will also identify understock-scion genotype combinations that respond well to flowering and seed set through grafting.