Development of common bean varieties tolerant to high temperatures in Mozambique


The IIAM Bean Breeding Team, 2023. Left to right: Mr Nildo Nhampossa, Mr Simao Willian, Dr Bento Filipe Francisco, Dr Celestina Jochua (PI), Dr Manuel Amane.
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PROJECT OVERVIEW
Background
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In Mozambique, the major common bean production areas are located at high altitudes in the central and northern regions, where the crop is cultivated under rainfed conditions. However, in southern Mozambique, high temperatures during the rainy season limit bean cultivation to irrigated systems during the dry season in lowland areas. In recent years, increases in both minimum and maximum average temperatures have adversely affected common bean productivity, resulting in shortages that threaten food security and nutrition, as well as reducing income opportunities.
To address this challenge, it is essential to develop heat-tolerant common bean varieties suitable for these regions.
In previous projects, IIAM evaluated various collections of common bean genotypes during the hot season in Chókwè, including populations derived from crosses between tepary bean (Phaseolus acutifolius) and common bean. The findings suggest that tepary lines could serve as valuable sources of heat stress tolerance, contributing to the improvement of common bean breeding programmes.
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Objectives
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To develop common bean varieties adapted to high temperature in Mozambique.
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To characterise and create database of races or pathotypes of the bean rust pathogen present in the main bean production regions and identify sources of resistance to bean rust.
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To introgress rust resistance genes into local susceptible commercial varieties and advanced breeding lines using MAS.
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To develop KASP (Kompetitive allele specific PCR) molecular markers linked to bean rust resistance.

Evaluation of common bean lines under farmer’s conditions in Chokwe (Feb 2023).

Evaluation of common bean lines on station Chokwe (Feb 2023).
Progress to date
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The first phase of the project identified 16 promising bean lines from a collection of 90 bean lines derived from crosses between common bean and tepary bean. These selected bean lines will be included in advanced field test and will also be used as parents to develop bean varieties tolerant to high temperature.
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Twenty-four (24) lines selected from previous projects for tolerance to abiotic stresses that include high temperature, drought and low phosphorus were tested and 10 promising lines have been identified. Seven (7) promising lines were tested under famer conditions in the hot season and 2 lines (IBC 301-204 and MHR 311-17) gave the highest yield. Participatory variety selection (PVS) was performed for the 24 lines and 5 preferred bean lines were and they are being evaluated for potential release as varieties or to be used as parents in breeding programmes.
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In preparation for field trials during the 2025 rainy season, seed of diverse common bean lines—identified as promising for release in the KT-funded pilot project—was multiplied at the Chókwè Research Station during the 2024 cool season.
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The team has also begun laying the foundation for a breeding programme to incorporate rust resistance and heat tolerance into farmer-preferred varieties. To characterise and create a database of races or pathotypes of the bean rust pathogen present in Mozambique’s major bean growing regions, infected leaves were collected from eight fields across southern Mozambique (Maputo and Gaza provinces). From this material, the team expects to derive over 200 isolates, which will be tested for virulence.
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A collection of germplasm from various sources was acquired, which will be evaluated as potential donors of rust resistance and tolerance to high temperature stress. Planned screening using molecular markers will be initiated and after completing the molecular lab that is being established.
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Seed multiplication at Chókwè Research Station of 300 lines derived from crosses between common and tepary bean in 2022 (i); Kufuna (ii); and Tiyela (iii); common bean varieties adapted to soils with low Phosphorous content bred by Dr Jochua; field preparation for the evaluation of tepary and common bean hybrids grown in the hot season at Chókwè Research Station (iv); and at farmers' fields for participatory evaluation of sex of the best performing lines (v).
PROJECT TEAM MEMBERS
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Dr Celestina Jochua
Principal Investigator, Instituto de Investigação Agrária de Moçambique (IIAM).
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Dr Jochua leads the KT-funded bean improvement programme in Mozambique. She holds a PhD in Plant Nutrition from Penn State University, USA, and an MSc in Biological Sciences - Plant Pathology, University of Nebraska, Lincoln, USA.

Dr Manuel Amane
Co-PI

Dr Samuel Camilo Salima
Co-PI

Dr Bento Filipe Francisco
Co-PI

Mr Nildo Nhampossa
Technician

Mr Simão William
Technician