Floret development and grain setting differences between modern durum wheats under contrasting nitrogen availability.

Area of Science:

• Agricultural Science
• Plant Physiology
• Agronomy

Background:

• Wheat yield is primarily determined by grain number per square meter.
• Grain number is closely linked to the number of fertile florets at anthesis.
• Understanding floret dynamics is crucial for improving durum wheat productivity.

Purpose of the Study:

• To investigate the effects of nitrogen and water availability on floret development in durum wheat.
• To identify cultivar-specific responses to nutrient and water management for optimizing grain number.
• To elucidate the mechanisms underlying floret generation and degeneration.

Main Methods:

• Field experiments conducted over two growing seasons with contrasting nitrogen levels (50 and 250 kgN ha⁻¹) and water availability (irrigated and rainfed).
• Evaluation of four durum wheat cultivars, with specific focus on two exhibiting contrasting responses to nitrogen.
• Inclusion of a detillering treatment under optimal conditions to assess grain setting.

Main Results:

• Nitrogen fertilization increased the number of fertile florets by approximately 30%.
• Both nitrogen and water availability influenced floret developmental rates, with higher nitrogen enabling more florets to reach fertile stage.
• Cultivar differences were observed in response to nitrogen, affecting floret production and grain setting.

Conclusions:

• Nitrogen and water management are key factors in determining fertile floret number and, consequently, wheat yield.
• Cultivar selection can enhance the response to nitrogen fertilization for increased grain production.
• Accelerated floret primordia development and improved grain setting contribute to higher wheat yields under optimal conditions.