Floret development of durum wheat in response to nitrogen availability

Area of Science:

• Agricultural Science
• Plant Physiology
• Agronomy

Background:

• Nitrogen (N) fertilization is crucial for stabilizing and increasing durum wheat yields in Mediterranean regions.
• Wheat yield is strongly linked to grain number per area, influenced by floret development dynamics during stem elongation.
• Limited research exists on the specific role of floret developmental dynamics in determining grain yield response to N.

Purpose of the Study:

• To investigate if durum wheat's response to nitrogen (N) fertilization, under varying water availability, is linked to floret primordia development dynamics.
• To understand how N influences the transition of floret primordia to fertile florets, ultimately affecting grain yield.

Main Methods:

• Field experiments were conducted over two growing seasons with factorial combinations of N levels and water regimes (rainfed/irrigated).
• Measurements focused on floret initiation, abortion rates, and fertile floret development during stem elongation.
• Yield components, particularly grain number per spike, were analyzed in relation to N and water treatments.

Main Results:

• Nitrogen (N) fertilization significantly impacted yield, primarily through an increase in grain number per spike.
• Floret initiation rates were consistent across N levels and water regimes.
• The critical factor for yield response to N was a higher survival rate of initiated florets, attributed to reduced abortion and accelerated development.

Conclusions:

• Durum wheat's yield response to N is mediated by enhanced floret survival, not increased initiation.
• Nitrogen reduces floret abortion late in stem elongation, promoting more initiated primordia to become fertile florets by flowering.
• Optimizing N management is essential for maximizing grain number and yield in durum wheat production systems.