Inheritance of internode and culm length in hexaploid Triticale

Area of Science:

• Plant genetics
• Agronomy
• Quantitative genetics

Background:

• Triticale (x Triticum secale) is an important crop with variable height.
• Understanding the genetic basis of culm length is crucial for breeding programs.

Purpose of the Study:

• To investigate the genetic action controlling total culm length and its segments in hexaploid Triticale.
• To analyze heterosis, general combining ability (GCA), and additive effects for plant height.

Main Methods:

• Diallel cross of twelve hexaploid Triticale cultivars.
• Analysis of F1 and F2 generations for culm length and four partial lengths.
• Application of Griffing, Hayman, and Jinks models for genetic analysis.

Main Results:

• Heterosis for culm length is primarily attributed to the upper half of the culm.
• Additivity significantly influences culm length inheritance, particularly in lower internodes.
• Spanish cultivars exhibit positive GCA, increasing height, while Mexican cultivars show negative GCA, decreasing height.
• Partial dominance was observed for all five traits, with duplicate epistasis likely predominant.
• High positive correlations exist between total culm length and its components, especially genetic correlations.

Conclusions:

• Culm length in Triticale is controlled by a complex interplay of additive gene action, partial dominance, and significant environmental influence.
• Breeding strategies should consider the GCA of specific cultivars and the contribution of different culm segments to overall height.
• Understanding these genetic components is vital for developing improved Triticale varieties with desired height characteristics.