Articles
TOWARDS THE DEVELOPMENT OF A HIGHLY FERTILE POLYPLOID CRANBERRY
Article number
574_26
Pages
175 – 180
Language
English
Abstract
The American cranberry (Vaccinium macrocarpon Ait.) is a diploid (2n=24). There are potential advantages of higher ploidy cranberries, particularly enhanced flower bud set and increased fruit size; but these advantages are compromised by reduced fertility.
We were interested in developing fertile polyploid cranberries for the potential to increase yield, as well as a method of transgene containment to assist our genetic engineering program.
Three promising colchicine-induced polyploid individuals were selected for breeding to improve fertility in subsequent generations: polyploids of Pilgrim, a high fruit color Stevens x Ben Lear selection, and an embryo of mixed heritage.
Selfed progeny of these selections and hybrids between the ‘Pilgrim’ colchiploid and the other two parents were generated.
Pollen germination, fruit set, fruit size, seed set and seed germination were evaluated on a subset of the progeny that flowered in the greenhouse in 2000.
The best pollen germination obtained by individuals within each progeny group exceeded that of the their respective parents, up to 90%. Fruit set in the progeny ranged from 0% to 94% on cross-pollinated flowers.
Seed set ranged from zero up to an average of 12 seeds per berry.
Fruit size cannot be reliably measured in the greenhouse, but some of the polyploid plants had fruit size up to double that typically seen for diploid plants in the greenhouse (3.3 vs. 1.6 g). In general, selfed fruit had smaller size and lower seed set than cross-pollinated fruit.
Seed germination was variable in the resulting seed populations.
Some populations of seed had germination rates exceeding 90%, while seeds from other lines failed to germinate.
These preliminary results suggest that there is good potential to enhance fertility through breeding in polyploid cranberry.
For further evaluation, all the first generation polyploid plants as well as second generation seedlings will be evaluated with natural pollination.
Those genotypes demonstrating good fruit set will be tested for self fertility in the greenhouse before large scale field testing will proceed.
We were interested in developing fertile polyploid cranberries for the potential to increase yield, as well as a method of transgene containment to assist our genetic engineering program.
Three promising colchicine-induced polyploid individuals were selected for breeding to improve fertility in subsequent generations: polyploids of Pilgrim, a high fruit color Stevens x Ben Lear selection, and an embryo of mixed heritage.
Selfed progeny of these selections and hybrids between the ‘Pilgrim’ colchiploid and the other two parents were generated.
Pollen germination, fruit set, fruit size, seed set and seed germination were evaluated on a subset of the progeny that flowered in the greenhouse in 2000.
The best pollen germination obtained by individuals within each progeny group exceeded that of the their respective parents, up to 90%. Fruit set in the progeny ranged from 0% to 94% on cross-pollinated flowers.
Seed set ranged from zero up to an average of 12 seeds per berry.
Fruit size cannot be reliably measured in the greenhouse, but some of the polyploid plants had fruit size up to double that typically seen for diploid plants in the greenhouse (3.3 vs. 1.6 g). In general, selfed fruit had smaller size and lower seed set than cross-pollinated fruit.
Seed germination was variable in the resulting seed populations.
Some populations of seed had germination rates exceeding 90%, while seeds from other lines failed to germinate.
These preliminary results suggest that there is good potential to enhance fertility through breeding in polyploid cranberry.
For further evaluation, all the first generation polyploid plants as well as second generation seedlings will be evaluated with natural pollination.
Those genotypes demonstrating good fruit set will be tested for self fertility in the greenhouse before large scale field testing will proceed.
Publication
Authors
E.L. Zeldin, B.H. McCown
Keywords
Vaccinium macrocarpon, polyploid, colchicine, fertility, fruit set, transgene containment
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