Dynamics of floret initiation/death determining spike fertility in wheat as affected by Ppd genes under field conditions.

Paula Prieto,Helga Ochagavía,Gustavo A Slafer,Simon Griffiths,Roxana Savin

doi:10.1093/jxb/ery105

Paula Prieto, Helga Ochagavía + Show 3 more

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https://doi.org/10.1093/jxb/ery105

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Abstract

As wheat yield is linearly related to grain number, understanding the physiological determinants of the number of fertile florets based on floret development dynamics due to the role of the particular genes is relevant. The effects of photoperiod genes on dynamics of floret development are largely ignored. Field experiments were carried out to (i) characterize the dynamics of floret primordia initiation and degeneration and (ii) to determine which are the most critical traits of such dynamics in establishing genotypic differences in the number of fertile florets at anthesis in near isogenic lines (NILs) carrying photoperiod-insensitive alleles. Results varied in magnitude between the two growing seasons, but in general introgression of Ppd-1a alleles reduced the number of fertile florets. The actual effect was affected not only by the genome and the doses but also by the source of the alleles. Differences in the number of fertile florets were mainly explained by differences in the floret generation/degeneration dynamics, and in most cases associated with floret survival. Manipulating photoperiod insensitivity, unquestionably useful for changing flowering time, may reduce spike fertility but much less than proportionally to the change in duration of development, as the insensitivity alleles did increase the rate of floret development.

Highlights

IntroductionGains in the grain yield of wheat can be achieved by improving any of its major components, but significant gains would be almost exclusively dependent on increments in the number of grains per unit land area (Slafer et al, 2014)
Gains in the grain yield of wheat can be achieved by improving any of its major components, but significant gains would be almost exclusively dependent on increments in the number of grains per unit land area (Slafer et al, 2014).Grain number is mostly associated with the number of fertile florets produced (Kirby, 1988; Slafer and Andrade, 1993; Miralles et al, 1998, 2000) mainly because wheat is a cleistogamous species
We showed the details for the wild type, and for one near isogenic lines (NILs) with a single (AP+BCS+DP), one with a double (AGS+BCS+DP), and one with a triple (AGS+BCS+DS) substitution with insensitive alleles

Summary

Introduction

Gains in the grain yield of wheat can be achieved by improving any of its major components, but significant gains would be almost exclusively dependent on increments in the number of grains per unit land area (Slafer et al, 2014). Grain number is mostly associated with the number of fertile florets produced (Kirby, 1988; Slafer and Andrade, 1993; Miralles et al, 1998, 2000) mainly because wheat is a cleistogamous species. The importance of these environmental signals for these developmental phases lies in the effect they have on the organs that are being generated at that time and the fact that these organs are the building blocks of grain yield (Slafer et al, 1996; Slafer, 2003).

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