Scientists show which genetic loci is associated with bunch weight in highland banana

Scientists have, for the first time, located the position of major quantitative trait loci associated with bunch weight and its component traits in Matooke, the East African Highland cooking banana. This is an important breakthrough in efforts to speed up the breeding of improved high-yielding varieties for both food security and improved household incomes in the region.

Increasing banana bunch weight is a major objective in banana improvement since it determines yield. Little was known about the genetic factors regulating it.

Scientists, therefore, sought to understand the genetics underlying bunch weight and its component traits in banana. The components of bunch weight include several traits such as the number of hands and fruits, fruit length and circumference, and the diameter of both fruit and pulp.

Through a genome-wide association study (GWAS), researchers found that chromosome 3 was most associated with bunch weight in banana. This breakthrough has been published in a paper entitled “Association Genetics of Bunch Weight and its Component Traits in East African Highland Banana” in the Theoretical and Applied Genetics journal.

The team studied a banana population of 307 genotypes of the East African Highland banana in the IITA breeding program of the International Institute of Tropical Agriculture (IITA) under three different environmental conditions.

“The findings of the study will facilitate marker-assisted breeding which allows breeders to identify early in the breeding cycle hybrids with poor fruit-filling characteristics and hence low bunch weight, thus saving time and money,” says Rony Swennen, head of IITA’s banana breeding program and corresponding author of the paper.

Cooking banana is an important food and income crop for over 80 million people in the East African Great Lakes countries of Burundi, the Democratic Republic of Congo, Kenya, Rwanda, Tanzania, and Uganda.

The study was carried out by a team of researchers at IITA in Tanzania and Uganda in collaboration with researchers from the Department of Plant Breeding, Swedish University of Agricultural Sciences; Institute of Experimental Botany, Centre of the Region Haná for Biotechnological and Agricultural Research from Czech Republic; and Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, Katholieke Universiteit Leuven, Belgium.

It was supported with funding from the Bill & Melinda Gates Foundation and the European Regional Development Fund project, “Plants as a tool for sustainable global development” and contributions from the CGIAR Research Program on Roots, Tubers and Bananas (RTB).

The blog was first published on the IITA website