Significant progressive heterobeltiosis in banana crossbreeding

Michael Batte,Helena Persson Hovmalm,Violet Akech,Moses Nyine,Rodomiro Ortiz,Rony Swennen,Brigitte Uwimana,Mulatu Geleta,Allan Brown

doi:10.1186/s12870-020-02667-y

Abstract

BackgroundHeterobeltiosis is the phenomenon when the hybrid’s performance is superior to its best performing parent. Banana (Musa spp. AAA) breeding is a tedious, time-consuming process, taking up to two decades to develop a consumer acceptable hybrid. Exploiting heterobeltiosis in banana breeding will help to select breeding material with high complementarity, thus increasing banana breeding efficiency. The aim of this study was therefore to determine and document the level of heterobeltiosis of bunch weight and plant stature in the East African highland bananas, in order to identify potential parents that can be used to produce offspring with desired bunch weight and stature after a few crosses.ResultsThis research found significant progressive heterobeltiosis in cross-bred ‘Matooke’ (highland cooking) banana hybrids, also known as NARITAs, when grown together across years with their parents and grandparents in Uganda. Most (all except 4) NARITAs exhibited positive heterobeltiosis for bunch weight, whereas slightly more than half of them had negative heterobeltiosis for stature. The secondary triploid NARITA 17 had the highest heterobeltiosis for bunch weight: 249% versus its ‘Matooke’ grandparent and 136% against its primary tetraploid parent. Broad sense heritability (across three cropping cycles) for yield potential and bunch weight were high (0.84 and 0.76 respectively), while that of plant stature was very low (0.0035). There was a positive significant correlation (P < 0.05) between grandparent heterobeltiosis for bunch weight and genetic distance between parents (r = 0.39, P = 0.036), bunch weight (r = 0.7, P < 0.001), plant stature (r = 0.38, P = 0.033) and yield potential (r = 0.59, P < 0.001). Grandparent heterobeltiosis for plant stature was significantly, but negatively, correlated to the genetic distance between parents (r = − 0.6, P < 0.001).ConclusionsSuch significant heterobeltiosis exhibited for bunch weight is to our knowledge the largest among main food crops. Since bananas are vegetatively propagated, the effect of heterobeltiosis is easily fixed in the hybrids and will not be lost over time after the release and further commercialization of these hybrids.

Highlights

Heterobeltiosis is the phenomenon when the hybrid’s performance is superior to its best performing parent
The diseases are caused by pathogens which thrive in tropical conditions, the most important of which are Xanthomonas vasicola pv. musacearum leading to banana bacterial wilt [5], Pseudocercospora fijiensis, causing black Sigatoka or black leaf streak disease [6, 7], and Fusarium oxysporum f. sp. cubense causing fusarium wilt or Panama disease [8]
The aim of this study was to determine and document the level of heterobeltiosis of bunch weight and plant stature in secondary triploid East African highland banana hybrids, in order to identify potential primary tetraploid hybrids and triploid matooke cultivars to be used as parents of offspring with desired bunch weight and plant stature after crossing diploids with them, improving the efficiency of the banana breeding program

Summary

Introduction

Heterobeltiosis is the phenomenon when the hybrid’s performance is superior to its best performing parent. L.) are important food and cash crops to millions of people in the tropical and subtropical regions of the world [1]. They are grown in more than 135 countries. Bananas and plantains rank among the most important food crops in the developing world [2]. Musacearum) leading to banana bacterial wilt [5], Pseudocercospora fijiensis, causing black Sigatoka or black leaf streak disease [6, 7], and Fusarium oxysporum f. Plant breeding is a long process requiring efficient selection of suitable parents with desired traits to produce superior hybrids [12]

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