Differentiation between nucellar and zygotic citrus seedlings by leaf shape

Area of Science:

• Horticulture
• Plant Breeding
• Genetics

Background:

• Distinguishing between nucellar and zygotic citrus seedlings is crucial for breeding programs.
• Traditional methods can be labor-intensive and may not always provide clear differentiation.

Purpose of the Study:

• To evaluate the leaf length to leaf width ratio (L/W) as a simple criterion for differentiating nucellar and zygotic citrus seedlings.
• To determine the effectiveness of L/W in identifying seedling origin based on parental characteristics.

Main Methods:

• Studied the L/W ratio in progeny of citrus variety 'King' crosses, known to produce both nucellar and zygotic offspring.
• Analyzed L/W values to identify distinct classes corresponding to parental or intermediate values.

Main Results:

• Progeny segregated into two distinct L/W classes: one similar to the 'King' parent (nucellar), and another intermediate between 'King' and the pollen parent (zygotic).
• Population means for L/W in zygotic seedlings were intermediate between the respective parents.
• L/W proved effective when parents exhibited appreciable differences in this ratio.

Conclusions:

• The L/W ratio is a practical and effective tool for differentiating nucellar and zygotic citrus seedlings.
• This method simplifies seedling identification, particularly in breeding and propagation efforts where parental L/W values differ significantly.