TY - JOUR

T1 - Allometric analysis of the effects of density on reproductive allocation and Harvest Index in 6 varieties of wheat (Triticum)

AU - Qin, Xiao-liang

AU - Weiner, Jacob

AU - Qi, Lin

AU - Xiong, You-cai

AU - Li, Feng-min

PY - 2013

Y1 - 2013

N2 - Plants produce biomass and then allocate some of this biomass to reproduction. The pattern of reproductiveallocation is an important aspect of a plant’s reproductive strategy in nature and is closely linkedto yield and Harvest Index in cereal crops. Recent research has concluded that reproductive allocationshould be analyzed and interpreted allometrically because ratios or fractions such as Reproductive Effortor Harvest Index are size dependent. We investigated reproductive allocation of individuals in 6 varietiesof Triticum (wheat) grown at a wide range of densities. We harvested leaves, stems, spikes and grains ofindividual plants and analyzed the relationship between grain mass and vegetative mass allometrically.The large variation in density created large variation in plant mass and reproductive output. Most ofthe variation in individual yield (grain mass) was due to variation in plant size. There were significantdifferences among the varieties in the allometric exponent (slope of log–log relationship) of grain versusvegetative mass, such that some varieties produced higher yield (and therefore had a higher HarvestIndex) than others when plants were small, while others had higher yield at larger sizes. Thus, the HarvestIndex and its rank among varieties changed with plant size, which puts into question the practice ofselecting for Harvest Index when crop performance varies greatly among individuals, years or environments.Selection for a high Harvest Index when individuals are large may mean unintentional selectionfor a lower Harvest Index when individuals are smaller. We conclude that cereal breeders should focuson reproductive allometry when interpreting Harvest Index, and select for allometric patterns that aremost advantageous in a given agronomic context, especially when there is large variation in productivityamong individuals, locations or years.

AB - Plants produce biomass and then allocate some of this biomass to reproduction. The pattern of reproductiveallocation is an important aspect of a plant’s reproductive strategy in nature and is closely linkedto yield and Harvest Index in cereal crops. Recent research has concluded that reproductive allocationshould be analyzed and interpreted allometrically because ratios or fractions such as Reproductive Effortor Harvest Index are size dependent. We investigated reproductive allocation of individuals in 6 varietiesof Triticum (wheat) grown at a wide range of densities. We harvested leaves, stems, spikes and grains ofindividual plants and analyzed the relationship between grain mass and vegetative mass allometrically.The large variation in density created large variation in plant mass and reproductive output. Most ofthe variation in individual yield (grain mass) was due to variation in plant size. There were significantdifferences among the varieties in the allometric exponent (slope of log–log relationship) of grain versusvegetative mass, such that some varieties produced higher yield (and therefore had a higher HarvestIndex) than others when plants were small, while others had higher yield at larger sizes. Thus, the HarvestIndex and its rank among varieties changed with plant size, which puts into question the practice ofselecting for Harvest Index when crop performance varies greatly among individuals, years or environments.Selection for a high Harvest Index when individuals are large may mean unintentional selectionfor a lower Harvest Index when individuals are smaller. We conclude that cereal breeders should focuson reproductive allometry when interpreting Harvest Index, and select for allometric patterns that aremost advantageous in a given agronomic context, especially when there is large variation in productivityamong individuals, locations or years.

U2 - 10.1016/j.fcr.2012.12.011

DO - 10.1016/j.fcr.2012.12.011

M3 - Journal article

VL - 144

SP - 162

EP - 166

JO - Field Crops Research

JF - Field Crops Research

SN - 0378-4290

ER -