Seed Set Patterns in East African Cooking Bananas are Asymmetric in Bunches and Fruits

Abstract Background: Low female fertility in bananas is the biggest hurdle for banana breeding. The aim of this study was to determine seed set patterns in East African cooking bananas EACBs to inform future decisions on a more targeted approach of increasing seed set and subsequently banana breeding efficiency. Matooke (AAA) and Mchare (AA) bananas are genetically distinct but belong to the same genetic complex, they referred to as EACBs. Seed set patterns in ‘Enzirabahima’ (AAA), ‘Mshale’ (AA) and ‘Nshonowa’ (AA) all with residual fertility were examined after hand pollination with a highly male fertile wild banana ‘Calcutta 4’ (AA). Results: Seed set in ‘Enzirabahima’ is predominant in distal hands. Mchare cultivars have a slightly more even distribution of seeds in their hands compared to ‘Enzirabahima.’ There is a gradual increase in seed set from proximal to distal hands with a slight drop in the last hand. This pattern is more definite in ‘Enzirabahima’ and ‘Mshale’ while ‘Nshonowa’ has a somewhat inconsistent pattern. There is also a drop in seed set per 100 fruits per hand from small to larger bunches. However, larger bunches have a higher pollination success compared to smaller bunches. They therefor set more seed on 100 fruits per hand and per bunch basis if bunches without seed are accounted for. Pollination success rate increases from smaller to larger bunches of EACBs. Seed set is biased toward the distal third part of fruits of examined EACBs as well tetraploid Matooke hybrid ‘401K-1’ (AAAA) and improved diploid ‘Zebrina’ GF (AA) that were used for comparison. In comparison, in the highly female fertile ‘Calcutta 4,’ seed set is along the entire length of the fruit.Conclusion: Seed set bias in the distal hands and distal end of fruits suggests a systematic mechanism rather than a random occurrence. It is expected that this information will provide a foundation for increased crossbreeding efficiency in bananas.

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Seed Set Patterns in East African Highland Cooking Bananas Show Asymmetric Distribution in Bunches and Fruits

Agronomy ◽

10.3390/agronomy11040763 ◽

2021 ◽

Vol 11 (4) ◽

pp. 763

Author(s):

Allan Waniale ◽

Rony Swennen ◽

Settumba B. Mukasa ◽

Arthur K. Tugume ◽

Jerome Kubiriba ◽

...

Keyword(s):

Seed Set ◽

Gradual Increase ◽

Asymmetric Distribution ◽

East African ◽

Pollination Success ◽

Random Occurrence ◽

Hand Pollination ◽

Wild Banana ◽

Breeding Efficiency ◽

Targeted Approach

Low female fertility in bananas is the biggest hurdle for banana breeding. The aim of this study was to determine seed set patterns in East African Highland Cooking bananas (EAHBs) to inform future decisions on a more targeted approach of increasing seed set and subsequently banana-breeding efficiency. Matooke (AAA) and Mchare (AA) bananas are genetically distinct but belong to the same genetic complex, referred to as EAHBs. Seed set patterns in “Enzirabahima” (AAA), “Mshale” (AA), and “Nshonowa” (AA), all with residual fertility, were examined after hand pollination with a highly male fertile wild banana “Calcutta 4” (AA). Seed set in “Enzirabahima” is predominant in distal hands. Mchare cultivars have a slightly more even distribution of seeds in their hands compared to “Enzirabahima”. There is a gradual increase in seed set from proximal to distal hands with a slight drop in the last hand. This pattern is more definite in “Enzirabahima” and “Mshale”, while “Nshonowa” has a somewhat inconsistent pattern. There is also a drop in seed set per 100 fruits per hand from small to larger bunches. However, larger bunches have a higher pollination success compared to smaller bunches. They therefore set more seed on 100 fruits per hand and per bunch basis, if bunches without seed are accounted for. Pollination success rate increases from smaller to larger bunches of EAHBs. Seed set is biased toward the distal third part of fruits of examined EAHBs, as well as tetraploid Matooke hybrid “401K-1” (AAAA), and improved diploid “Zebrina” GF (AA) that were used for comparison. In comparison, in the highly female fertile “Calcutta 4”, seed set is along the entire length of the fruit. Seed set bias in the distal hands and distal end of fruits suggests a systematic mechanism rather than a random occurrence. It is expected that this information will provide a foundation for increased crossbreeding efficiency in bananas.

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Application of Pollen Germination Media on Stigmas during Pollination Increases Seed Set in East African Highland Cooking Bananas (Musa spp.)

Agronomy ◽

10.3390/agronomy11061085 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1085

Author(s):

Allan Waniale ◽

Rony Swennen ◽

Settumba B. Mukasa ◽

Arthur K. Tugume ◽

Jerome Kubiriba ◽

...

Keyword(s):

Pollen Germination ◽

Management Practices ◽

Seed Set ◽

East African ◽

Musa Spp ◽

Field Management ◽

Wild Banana ◽

Breeding Efficiency

Seed set in East African Highland Cooking bananas (EAHBs) is extremely low and therefore hampers breeding. Pollen–pistil interaction is a key contributing factor. We assessed the effect of pollen germination media (PGM) on seed set in EAHBs. Five EAHB cultivars were pollinated with pollen from the wild banana ‘Calcutta 4’. Glucose-based PGM sprayed on freshly emerged stigmas significantly increased seed set per 100 fruits per bunch. Increases were 73.5% in ‘Enzirabahima’, 39.9% in ‘Mshale’, and 302.4% in ‘Nshonowa’. However, PGM did not increase seed set in the female sterile ‘Mlelembo’ and ‘Nakitembe’. As larger bunches were more fertile, good field management practices are also recommended to get more seed to improve breeding efficiency.

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Seed Set Patterns in East African Highland Cooking Bananas Are Dependent on Weather before, during and after Pollination

Horticulturae ◽

10.3390/horticulturae7070165 ◽

2021 ◽

Vol 7 (7) ◽

pp. 165

Author(s):

Allan Waniale ◽

Rony Swennen ◽

Settumba B. Mukasa ◽

Arthur K. Tugume ◽

Jerome Kubiriba ◽

...

Keyword(s):

Critical Period ◽

Floral Development ◽

Seed Set ◽

Correlation Coefficients ◽

Principal Component ◽

Maximum Temperature ◽

Fruit Pulp ◽

East African ◽

Average Temperature ◽

Wild Banana

Seed set in banana is influenced by weather, yet the key weather attributes and the critical period of influence are unknown. We therefore investigated the influence of weather during floral development for a better perspective of seed set increase. Three East African highland cooking bananas (EAHBs) were pollinated with pollen fertile wild banana ‘Calcutta 4′. At full maturity, bunches were harvested, ripened, and seeds extracted from fruit pulp. Pearson’s correlation analysis was then conducted between seed set per 100 fruits per bunch and weather attributes at 15-day intervals from 105 days before pollination (DBP) to 120 days after pollination (DAP). Seed set was positively correlated with average temperature (P < 0.05–P < 0.001, r = 0.196–0.487) and negatively correlated with relative humidity (RH) (P < 0.05–P < 0.001, r = −0.158–−0.438) between 75 DBP and the time of pollination. After pollination, average temperature was negatively correlated with seed set in ‘Mshale’ and ‘Nshonowa’ from 45 to 120 DAP (P < 0.05–P < 0.001, r = −0.213–−0.340). Correlation coefficients were highest at 15 DBP for ‘Mshale’ and ‘Nshonowa’, whereas for ‘Enzirabahima’, the highest were at the time of pollination. Maximum temperature as revealed by principal component analysis at the time of pollination should be the main focus for seed set increase.

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Seed Set Patterns in East African Cooking Bananas (Musa spp.) are Dependent on Weather Before, During, and After Pollination

10.21203/rs.3.rs-38376/v1 ◽

2020 ◽

Author(s):

Allan Waniale ◽

Settumba B. Mukasa ◽

Arthur K. Tugume ◽

Robooni Tumuhimbise ◽

Jerome Kubiriba ◽

...

Keyword(s):

Seed Set ◽

Correlation Coefficients ◽

Maximum Temperature ◽

East African ◽

Ripe Fruit ◽

Data Set ◽

Breeding Programs ◽

Average Temperature ◽

Wild Banana ◽

Time Of Harvest

Abstract Background: Seed set in banana (Musa spp.) is influenced by weather but the most critical weather attribute(s) and the critical period are unknown. Such information is of paramount importance to increase seed set for banana breeding programs. Three female fertile East African cooking bananas (EACBs), ‘Enzirabahima’ (AAA), ‘Mshale’ (AA), and ‘Nshonowa’ (AA) were pollinated with the highly male fertile wild banana ‘Calcutta 4’ (AA). At full maturity, bunches were harvested and ripened and seeds extracted from ripe fruit pulp. Seed set was then correlated with weather before, during, and after pollination.Results: Seed set was positively correlated with high temperatures (r=0.172 – 0.488), solar radiation (r=0.181 – 0.282) and negatively correlated with rainfall (r=-0.214 – -0.238) and relative humidity (RH) (r=-0.158 – -0.438) between 75 and 15 days before pollination (DBP). The pattern of weather association was cultivar-dependent with ‘Nshonowa’ having the strongest significant associations. At the time of pollination, high average temperatures were critical for seed set in ‘Enzirabahima’ (r=0.214, P<0.01) while high morning RH was critical for ‘Mshale’ (r=0.299, P<0.01). After pollination, high morning temperatures were associated with seed set (r=0.150 – 0.429) between 15 days to 90 days after pollination (DAP). High average temperatures were negatively correlated with seed set in ‘Mshale’ and ‘Nshonowa’ from 45 DAP to time of harvest (r=-0.208 – -0.344). Coefficients of correlation were generally highest 15 DBP especially for ‘Mshale’ and ‘Nshonowa.’ Principle component analysis showed that average and maximum temperature are the most important variables in the entire data set. Conclusion: Coefficients of correlation were generally less than 0.5 partly as a result of weather involvement in seed set at several floral development stages; before, during, and after pollination. The most critical developmental stage is 15 DBP especially for ‘Mshale’ and ‘Nshonowa’ as they had the high correlation coefficients. Average temperature should be the main focus for seed set increase in banana.

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Hand-Pollination ofCardamine californicaImproves Seed Set

Native Plants Journal ◽

10.2979/npj.2006.7.3.248 ◽

2006 ◽

Vol 7 (3) ◽

pp. 248-252 ◽

Cited By ~ 2

Author(s):

Kazuki Ariyoshi ◽

Emily Magnaghi ◽

Mark Frey

Keyword(s):

Seed Set ◽

Hand Pollination

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A comparison of flower-visiting insects to rare Symphyotrichum sericeum and common Solidago nemoralis (Asteraceae)

Botany ◽

10.1139/b10-003 ◽

2010 ◽

Vol 88 (3) ◽

pp. 241-249 ◽

Cited By ~ 5

Author(s):

Diana Bizecki Robson

Keyword(s):

Seed Set ◽

Visitation Rate ◽

Hand Pollination ◽

Insect Visitation ◽

The Common ◽

Insect Activity ◽

Flower Visiting ◽

Common Plant ◽

Insect Visitors ◽

Over Time

Flower-visiting insect activity to the rare Symphyotrichum sericeum (Vent.) G.L. Nesom and the common Solidago nemoralis Ait. var. longipetiolata (Mack. & Bush) Pal. & Steyerm. was examined to detect compositional and temporal similarities. A hand pollination experiment was conducted to determine whether pollen was limiting seed set. Of the 31 insect taxa that visited these plants, Bombus bifarius Cresson was the most common visitor to both species. More insect visitors of the Halictidae and Bombyliidae were received by S. sericeum than S. nemoralis, which received more visitors of the Syrphidae and Tachinidae. The insect visitation rate was not significantly different between the two plant species. Solidago nemoralis was visited by fewer insect taxa per day than S. sericeum, but the constancy of its visitors was higher. The insect visitor composition changed over time, with B. bifarius ignoring S. sericeum plants initially, then visiting them more frequently as the number of receptive S. nemoralis capitula declined. Hand pollination increased seed set in the earliest flowering capitula of S. sericeum, but not for those flowering during the peak. This research shows that the quantity of insect visits to the rare plant is comparable with that of the common plant but that pollination quality may be lower, particularly for early blooming capitula.

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Why so many flowers? A preliminary assessment of mixed pollination strategy enhancing sexual reproduction of the invasive <i>Acacia longifolia</i> in Portugal

Web Ecology ◽

10.5194/we-18-47-2018 ◽

2018 ◽

Vol 18 (1) ◽

pp. 47-54 ◽

Cited By ~ 1

Author(s):

Manuela Giovanetti ◽

Margarida Ramos ◽

Cristina Máguas

Keyword(s):

Invasive Plant ◽

Seed Set ◽

Pollen Grains ◽

Striking Difference ◽

Pollination Syndromes ◽

Pollination Success ◽

Relative Contribution ◽

Acacia Longifolia ◽

Exclusion Experiments ◽

Pollination Strategy

Abstract. Acacia longifolia, a native legume from Australia, has been introduced in many European countries and elsewhere, thus becoming one of the most important global invasive species. In Europe, its flowering occurs in a period unsuitable for insect activity: nonetheless it is considered entomophilous. Floral traits of this species are puzzling: brightly coloured and scented as liked by insects, but with abundant staminate small-sized flowers and relatively small pollen grains, as it is common in anemophilous species. Invasion processes are especially favoured when reshaping local ecological networks, thus the interest in understanding pollination syndromes associated with invasive plant species that may facilitate invasiveness. Moreover, a striking difference exists between its massive flowering and relatively poor seed set. We introduced a novel approach: first, we consider the possibility that a part of the pollination success is carried on by wind and, second, we weighted the ethological perspective of the main pollinator. During the flowering season of A. longifolia (February–April 2016), we carried on exclusion experiments to detect the relative contribution of insects and wind. While the exclusion experiments corroborated the need for pollen vectors, we actually recorded a low abundance of insects. The honeybee, known pollinator of acacias, was relatively rare and not always productive in terms of successful visits. While wind contributed to seed set, focal observations confirmed that honeybees transfer pollen when visiting both the inflorescences to collect pollen and the extrafloral nectaries to collect nectar. The mixed pollination strategy of A. longifolia may then be the basis of its success in invading Portugal's windy coasts.

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INFLUENCE OF MOISTURE STRESS, RELATIVE HUMIDITY AND OXYGEN DIFFUSION RATE ON SEED SET AND YIELD OF WHEAT

Canadian Journal of Plant Science ◽

10.4141/cjps69-003 ◽

1969 ◽

Vol 49 (1) ◽

pp. 29-37 ◽

Cited By ~ 9

Author(s):

C. A. Campbell ◽

D. S. McBean ◽

D. G. Green

Keyword(s):

Soil Moisture ◽

Relative Humidity ◽

Oxygen Diffusion ◽

Seed Set ◽

Diffusion Rate ◽

Moisture Stress ◽

Morphological Examination ◽

Hand Pollination ◽

Growth Chamber Studies ◽

Oxygen Diffusion Rate

The influence of oxygen diffusion rate (ODR) and relative humidity (RH) on seed set and yield of wheat was investigated in two growth chamber studies. In one study, plants grown at 80% RH were compared with those grown at 60%. In the other, plants grown in pots without supplemental aeration were compared with plants grown in aerated pots.Wheat grown at low soil moisture stress (between 25 and 16%) produced significantly poorer seed set and grain yield than those grown at higher stress (between 25 and 10%). Seed set was less severely reduced in Manitou than in Chinook. Plants grown at low moisture stress and 60% RH gave better seed set than those grown at 80%. However, even at 60% RH, seed set was less than 65%.The oxygen diffusion rates in unaerated pots were 28 × 10−8, 100 × 10−8 and 200 × 10−8 g cm−2min−1 at 25%, 16% and 10% soil moisture (by weight). In aerated pots, ODR at 25% and 16% soil moisture were 82 × 10−8 and 180 × 10−8 g cm−2min−1, respectively.Seed set and grain yields of Chinook wheat grown at low moisture stress were increased from 54 to 82% and from 11.5 to 26.7 g/pot by improving the soil aeration.The anthers, especially the pollen, were the main reproductive components damaged by poor aeration. This was demonstrated by morphological examination and by hand-pollination experiments. Poor seed set was confined primarily to the top two-thirds of the head.

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Breeding Systems of Disjunct Populations of Christmas Bells (Blandfordia grandiflora R.Br., Liliaceae): Variation in Self-Fertility and an Ovular Mechanism Regulating Self-Fertilisation

Australian Journal of Botany ◽

10.1071/bt9930035 ◽

1993 ◽

Vol 41 (1) ◽

pp. 35 ◽

Cited By ~ 13

Author(s):

M Ramsey ◽

N Prakash ◽

S Cairns

Keyword(s):

Seed Set ◽

Pollen Tubes ◽

Breeding Systems ◽

Seed Abortion ◽

Self Incompatibility ◽

Coastal Plants ◽

Hand Pollination ◽

Disjunct Populations ◽

Pollen Vectors ◽

Blandfordia Grandiflora

The breeding systems of disjunct tableland and coastal populations of Christmas bells were determined using hand-pollination experiments. In both populations, 90% or more of self-pollinated plants produced seeds. Tableland plants were significantly more self-fertile than coastal plants (ratio of self seed set to cross seed set: tableland, 0.55 ± 0.03; coast, 0.08 ± 0.02). Significant variation among plants for self-fertility was found in both populations. Autofertility was 1.6% or less in both populations indicating that pollen vectors are necessary for seed set. Seed set by agamospermy in both populations was less than 0.1%. Percentage seed abortion was greater in self-pollinated plants than cross-pollinated plants in both populations. In both self- and cross-pollinated plants, seed abortion was twice as great in the coastal population than in the tableland population. No evidence was found for stigmatic or stylar self-incompatibility. Self and cross pollen adhered to and germinated equally well on stigmas in both populations (72 - 77% germination). Similarly, there were no differences between pollination treatments or populations in the percentage of ovules penetrated by pollen tubes (82 - 89% penetration). When self-pollination preceded cross-pollination by 24 h or longer seed set was significantly reduced compared to flowers that were cross-pollinated only, suggesting ovules were pre-empted by self pollen tubes. Collectively these results strongly suggest that self seed set was reduced by a mechanism operating at the ovule level, such as early-acting inbreeding depression due to recessive seed-aborting genes, although incomplete late-acting self-incompatibility cannot be ruled out. For coastal plants, this ovular mechanism largely prevents selfing, indicating plants were predominantly outcrossing although most produced some self seed. For tableland plants, substantial seed set by selfing may occur under natural conditions.

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Use of timelapse photography to determine flower opening time and pattern in banana (Musa spp.) for efficient hand pollination

Scientific Reports ◽

10.1038/s41598-021-98500-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Allan Waniale ◽

Rony Swennen ◽

Settumba B. Mukasa ◽

Arthur K. Tugume ◽

Jerome Kubiriba ◽

...

Keyword(s):

Seed Set ◽

Digital Camera ◽

Female Flower ◽

Time Lapse ◽

Temporal Separation ◽

Flower Opening ◽

Main Challenge ◽

Hand Pollination ◽

Male Flowers ◽

Female Flowers

AbstractSterility and low seed set in bananas is the main challenge to their conventional genetic improvement. The first step to seed set in a banana breeding program depends on pollination at the right time to ensure effective fertilization. This study aimed at determining bract opening time (BOT) to enhance efficient pollination and seed set in bananas. A Nikon D810 digital camera was set-up to take pictures of growing banana inflorescences at five-minute intervals and time-lapse movies were developed at a speed of 30 frames per second to allow real-time monitoring of BOT. Genotypes studied included wild banana (1), Mchare (2), Matooke (4), Matooke hybrid (1), and plantain (1). Events of bract opening initiated by bract lift for female flowers (P < 0.01) started at 16:32 h and at 18:54 h for male flowers. Start of bract rolling was at 18:51 h among female flowers (P < 0.001) and 20:48 h for male flowers. Bracts ended rolling at 02:33 h and 01:16 h for female and flowers respectively (P < 0.05). Total time of bract opening (from lift to end of rolling) for female flowers was significantly longer than that of male flowers (P < 0.001). On average, the number of bracts subtending female flowers opening increased from one on the first day, to between one and four on the fourth day. The number regressed to one bract on day eight before start of opening of bracts subtending male flowers. There was a longer opening interval between bracts subtending female and male flowers constituting spatial and temporal separation. Bract rolling increased from partial to complete rolling from proximal to the distal end of the inflorescence among female flower. On the other hand, bracts subtending male flowers completely rolled. Differences in BOT of genotypes with the same reference time of assessment may be partly responsible for variable fertility. Hand pollination time between 07:00 and 10:00 h is slightly late thus an early feasible time should be tried.

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