Xenia and Maternal Effects on Maize Agronomic Traits at Three Plant Densities

Abstract

Kernel mass is a primary yield component in maize (Zea mays L.) governed by both xenia and maternal effects. Because kernel growth depends on assimilate supply, we wanted to learn if kernel-weight genes also affect plant size and agronomic characters. We reciprocally crossed three strains known to differ for rates of grain filling [high (HC), random (RC), and low (LC) R-nj color] with two kernel-weight strains [large (LG), and small (SM)] to produce 12 hybrid strains. For 2 yr at two locations, we grew plants of each hybrid at 24 000, 48 000, and 72 000 plants ha-~ in plots arranged so that wind pollinated silks with either LG or SM pollen. Leaf number, leaf width, leaf length, and time to silk were measured to compute leaf area and average leaf expansion rate (ALER). We also measured grain yield and grain moisture concentration at harvest. In one of four environments, " hybrids pollinated by the LG strain had 34% higher yields and 24 g kg-~ lower harvest moisture than hybrids pollinated by the SM strain. Increasing plant density delayed silking, increased leaves per plant, and decreased leaf width. Hybrid plants from the LG strain yielded 10% more than hybrid plants from the SM strain. They also had 12% higher grain moisture at harvest, 11% greater leaf surface area (mainly from more and wider leaves), and silked 0.6 d later than SM plants. Hybrid plants from the HC strain produced higher grain yields and greater leaf surface areas than plants from the RC or the LC strains. Leaf surface area was correlated (r = 0.80, P < 0.01) with grain yield. Kernel growth genes influenced yield via xenia effects but mainly by genes in the plant. Although R-nj color genes only increased yields of specific reciprocal hybrids, in properly planned hybrids these genes may complement genes that increase yield via larger kernels.

Genotype × Environment Interaction for Plant Density Response in Maize (Zea mays L.)

“…A comparative study of commercial hybrids introduced from 1930 to 2001 showed an average increase in grain yield of 0.09 Mg ha -1 yr -1 (based on year of introduction of the hybrid) when hybrids were compared at 7.9 plants m -2 versus an average increase of only 0.014 Mg ha -1 yr -1 when hybrids were compared at 1.0 plants m -2 (Duvick, 2005). Numerous authors have examined the effect of plant density on relative differences among hybrids and other types of maize cultivars (Bavec and Bavec, 2002;Brekke et al, 2011aBrekke et al, , 2011bCarena and Cross, 2003;Carlone and Russell, 1987;Duvick, 2005;Duvick et al, 2004;Gonzalo et al, 2010;Russell, 1974Russell, , 1984Russell, , 1986Russell, , 1991Sangoi et al, 2002;Seka and Cross, 1995;Singh et al, 2011;Tollenaar, 1992;Widdicombe and Thelen, 2002). However, in few of the cited papers have environmental effects and genotype ´ environment interactions (G ´ E) for density response been addressed in great detail.…”

Selection and Adaptation to High Plant Density in the Iowa Stiff Stalk Synthetic Maize (Zea mays L.) Population

“…While Widdicombe and Thelen (2002) found an increase in test weight at high density, the increase was small, suggesting any impact of density was minimal. Seka and Cross (1995) found a linear response of grain moisture to increasing density, and Widdicombe and Thelen (2002) found a decrease in moisture at higher plant densities. However, Carena and Cross (2003) did not find an effect of plant density on grain moisture.…”

Maternal control of seed weight in rapeseed (Brassica napus L.): the causal link between the size of pod (mother, source) and seed (offspring, sink)

“…are theoretically determined by both maternal (nuclear and cytoplasmic) and zygotic (embryo and endosperm) effects. The genetic analyses of reciprocal crosses in several species, including Arabidopsis (Alonso‐Blanco et al ., ), maize (Seka and Cross, ; Zhang et al ., ), wheat (Minhas et al ., ), cotton (Pahlavani and Abolhasani, ), peanut (Hariprasanna et al ., ), sorghum (Mohammed et al ., ), pea (Lemontey et al ., ) and bean (Duc et al ., ; Singh et al ., ), have shown that both maternal and xenia (via zygote) effects have significant roles on seed size/weight. However, the relative importance of maternal and zygotic effects has not been analyzed and thus is unclear in rapeseed, in spite of its fundamental interest and significance in genetic study and breeding.…”