A doctoral dissertation at the Faculty of Agriculture on the impact of developing first-generation hybrids of cherry tomatoes through the method of half-diallel crossbreeding under the influence of boron foliar spraying.

The Faculty of Agriculture at the University of Diyala defended a doctoral dissertation entitled “Development of First-Generation Hybrids of Cherry Tomatoes Through Half-Diallel Crossbreeding and the Effect of Boron Foliar Spraying.”

The study, presented by the student Saja Ahmed Najm Al-Tayyari, focused on generating individual hybrids of cherry tomatoes using the half-diallel crossbreeding method and producing a range of individual hybrids. These hybrids were evaluated through half-diallel crosses among six selected cherry tomato lines, chosen based on their genetic diversity. The study also assessed genetic parameters and the hybrid vigor (heterosis) of all developed hybrids. Furthermore, it investigated the impact of boron foliar spraying on the quantitative and qualitative traits of cherry tomato plants.

Several key conclusions were drawn from the research:

1. The pure cherry tomato lines used in the experiment were genetically diverse and phenotypically distinct, making them suitable as parents for producing individual hybrids.

2. Boron foliar spraying at a concentration of 100 mg/L improved all vegetative growth traits, yield, and chemical properties.

3. Parent (1) LA2838 exhibited strong general combining ability, indicating its potential as a promising parent.

4. The hybrids 3×4, 2×4, and 2×1 demonstrated significant increases in yield per plant, reaching 2.98, 2.96, and 2.94 kg, respectively.

The study provided several recommendations:

• It is essential to preserve the six pure lines used in the research from mechanical genetic contamination and maintain them as parents, as their hybrids displayed high, significant hybrid vigor and excelled in vegetative growth, yield, and chemical traits.

• Continued production of individual hybrids such as [5×6], [1×4], [2×4], [5×2], and [2×1] is recommended, as these hybrids showed desirable and significant performance across most studied traits, including yield and its components.

• The hybrids [5×6], [2×4], and [1×6] can be incorporated into breeding programs, given their demonstration of hybrid vigor for most desirable traits.