Efficient method for generating citrus hybrids with polyembryonic Satsuma mandarin as the female parent

Area of Science:

• Plant Breeding and Genetics
• Horticulture
• Citrus Research

Background:

• Polyembryonic citrus seeds contain multiple nucellar embryos and one zygotic embryo, complicating crossbreeding.
• Nucellar embryos are typically considered more vigorous than zygotic embryos, influencing propagation strategies.
• In vitro embryo rescue is commonly used for zygotic embryo recovery, but its efficiency relative to simpler methods is not well-established.

Purpose of the Study:

• To compare the effectiveness of in-soil seed sowing versus in vitro embryo rescue for obtaining hybrids from polyembryonic Satsuma mandarin.
• To evaluate the efficiency and practicality of each method for hybrid selection in citrus breeding.

Main Methods:

• Utilized polyembryonic Satsuma mandarin as the female parent.
• Compared embryo development and hybrid recovery rates between seeds sown directly in soil and those cultured in vitro.
• Assessed the ratio of hybrids to the total resulting population for each method.

Main Results:

• The in-soil method yielded less than one-third the number of mature embryos per seed compared to the in vitro method.
• While in vitro culture produced more total hybrids, the in-soil method resulted in a significantly higher ratio of hybrids within the population.
• Individuals obtained via the in-soil method showed comparable growth to nucellar embryos, suggesting zygotic embryos are viable under this condition.

Conclusions:

• The in-soil seed sowing method is more efficient and practical for selecting hybrids from polyembryonic Satsuma mandarin seeds.
• This study demonstrates the viability and effectiveness of the in-soil method, offering a cost-effective and simpler alternative to in vitro techniques.
• Findings suggest zygotic embryos in selected Satsuma mandarin crosses exhibit robust growth when propagated via the in-soil method.