Enhancing seed set and viability in diploid banana ( Musa spp.) through irrigation

Banana ( Musa spp.) is a vital staple and cash crop in tropical regions, sustaining millions of people and contributing significantly to food security and income. In Tanzania, the Mchare variety is particularly important as a staple crop and serves as a key progenitor for globally significant cultivars such as Cavendish and Gros Michel. Despite its importance, Mchare faces several challenges, including susceptibility to pests and diseases and, notably, low seed set and poor seed viability, which constrain breeding. This study investigated the impact of supplemental irrigation on seed production and viability in Mchare bananas ‘Huti-White’ under controlled field conditions. The experiment was conducted at the Nelson Mandela African Institution of Science and Technology. A total of 320 ‘Huti-White’ suckers were planted under a randomized complete block design with factorial combinations of irrigation (supplemental irrigation (IR) vs rainfed (RF)), planting cycle and season. Supplemental irrigation was applied through drip irrigation, delivering 1360 mm of water over 17 weeks during the dry season and resulting in a total annual input of 2263 mm per mat ( banana mat is a cluster of banana plants growing from the same corm). Data were analysed in R (v4.3.0) using ANOVA, with mean separation performed using least significant difference (LSD) tests at the 5% level. Results showed that supplemental irrigation significantly affected both seed quantity and quality. Total seeds extracted were significantly affected by supplemental irrigation ( p < 0.001, LSD = 2.26), with RF mats producing more seeds. However, seed quality was markedly lower under RF conditions, with 55.9% of seeds lacking embryos compared with 6.9% under supplemental irrigation ( p < 0.001, LSD = 1.37). Germination efficiency relative to total seeds was higher under supplemental irrigation (85.2%) than RF (33.7%), and seed viability was significantly greater ( p = 0.015, LSD = 7.55%), with 91.5% of embryo-bearing seeds germinating compared with 76.3% under RF conditions. Cycle and seasonal effects were not significant, identifying supplemental irrigation as the dominant factor affecting reproductive success. Although RF plants produced more seeds numerically, most were non-functional, whereas supplemental irrigation markedly improved embryo retention, germination efficiency and seed viability, with clear implications for banana breeding and germplasm development. Significance of the study What is already known on this subject? Banana ( Musa spp.) improvement, particularly in East African Mchare types, is constrained by low seed viability, which limits the efficiency of breeding programmes. Previous studies have established that environmental factors, especially water availability, play a critical role in influencing seed set and reproductive success. Despite this understanding, most research has focused on increasing seed quantity rather than improving seed quality. What are the new findings? This study demonstrates that water availability during the reproductive stage is the primary determinant of seed quality rather than seed quantity, revealing a clear quantity–quality trade-off regulated by irrigation. Under rainfed conditions, plants produced a higher number of seeds, indicating that fertilisation processes such as pollen deposition and stigma receptivity were not completely inhibited. However, a large proportion of these seeds lacked embryos or failed to germinate, suggesting substantial post-fertilisation failure. In contrast, supplemental irrigation resulted in fewer seeds but significantly improved embryo formation, germination rates, and overall seed viability. This resulted in a higher proportion of functional seeds, even when total seed output was lower. What is the expected impact on horticulture? The findings provide a practical and impactful strategy for improving banana breeding efficiency, particularly in water-limited environments. By applying targeted supplemental irrigation during the reproductive phase, breeders can significantly enhance seed viability, increase the proportion of embryo-bearing seeds, and reduce the production of non-functional seeds. This represents a paradigm shift in horticultural practice from maximising seed quantity to optimising seed quality. These insights have direct implications for breeding programmes, where seed viability is a critical limiting factor. Integrating irrigation into reproductive-stage management can accelerate breeding cycles, improve hybridisation success, and enhance the development of improved banana cultivars.