Effects of In Vitro Polyploidization on Agronomic Characteristics and Fruit Carotenoid Content; Implications for Banana Genetic Improvement

Abstract

Bananas (Musa spp.), native to South East Asia, have spread worldwide and are integrated into the diets of millions of people in tropical regions. Carotenoid content varies dramatically between different banana genotypes, providing an opportunity for vitamin A biofortification. Polyploidization is a useful tool for crop improvement with potential to generate new diversity, especially in a polyploid crop like bananas. Ten induced tetraploids generated from six diploid banana genotypes were evaluated for their agronomic attributes and fruit carotenoid content in comparison to their diploid progenitors. Tetraploids had distinct plant morphology, but generally displayed inferior vegetative and yield characteristics with 20% lower bunch weights than their original diploids. Similarly, a 50% decrease in fruit provitamin A carotenoids (α-carotene, 13-cis β-carotene, 9-cis β-carotene, trans-β-carotene) accompanied by a corresponding increase in lutein was recorded in induced tetraploids in comparison to their original diploids. Additionally, all lines were subjected to pollen viability tests to assess their fertility. Pollen viability tests indicated over 70% viability for induced tetraploids and diploid controls, suggesting their possible use in crosses. These findings provide a basis for the application of induced polyploidization in bananas to generate useful genetic material for integration in hybridization programmes aiming to produce vitamin A enriched triploids valuable to malnourished populations.

A Novel Banana Mutant “RF 1” (Musa spp. ABB, Pisang Awak Subgroup) for Improved Agronomic Traits and Enhanced Cold Tolerance and Disease Resistance

“…Traditional genetic breeding has struggled to improve major agronomic traits and stress resistance in bananas, mainly due to its parthenocarpy and polyploidy (Ortiz and Swennen, 2014 ; Amah et al, 2019 ). Therefore, mutation breeding using in vitro propagated bananas has been proposed as a powerful approach to develop new cultivars or improved strains based on excellent cultivars (Karmarkar et al, 2001 ; Saraswathi et al, 2016 ; Datta et al, 2018 ).…”

“…According to the previous studies (Orjeda, 1998 ; Amah et al, 2019 ), key agronomic characteristics, namely, vegetative and yield traits, were separately evaluated at flowering time and at harvest time. The height of the pseudo-stem (HP), the pseudo-stem girth (PG) at 100 cm above the soil surface, and the plant base girth (PBG) were recorded at the time of flowering.…”

“…The traditional breeding method of genetic crossing has been applied with difficulty to dessert banana varieties, given the genetic characteristics of banana in general: parthenocarpic, polyploidy, irregular meiotic behavior, low fertility, and seed viability, among others (Heslop-Harrison and Schwarzacher, 2007 ; Jeridi et al, 2012 ; Arinaitwe et al, 2019 ; Batte et al, 2019 ). However, somatic cell mutations do not offer an effective approach for screening new varieties of banana (Bhagwat and Duncan, 1998 ; Karmarkar et al, 2001 ; Reyes-Borja et al, 2007 ; Uma et al, 2012 ; Amah et al, 2019 ). A mutation is, in principle, based on sudden heritable changes in the genetic material of an organism under abnormal genetic separation or recombination, such as spontaneous and induced mutations (Oladosu et al, 2015 ).…”

In vitro induction and characterisation of tetraploid drumstick tree (Moringa oleifera Lam.)

“…A number of studies have demonstrated that polyploid plants can vary in their morphology, ecology, physiology, and cytology compared to the parental line [ 1 , 6 , 9 , 27 ]. Such variations have been used successfully in plant breeding programmes to develop superior cultivars [ 8 , 28 , 29 , 30 ]. Here, we assessed a range of selected characteristics to identify significant differences between the diploid and tetraploid plants.…”

The Unique Existence of Chromosomal Abnormalities in Polyploidy Plants

“…Upregulating genes contributing to biosynthesis pathway of PTOX in autotetraploid Linum album enhanced content of podophyllotoxin (PTOX) plays a good example here [48]. Aiming to vitamin A enriching in triploid banana has been initiated by inducing tetraploid one from serval types of diploid and then conducting hybrid between them [49]. Much contents of total flavonoid and gastrodin significantly produced in Autotetraploid Anoectochilus formosanus Hayata [50].…”