Characteristics of Reproductive Abortion in Soybean¹

Abstract

The abortion of reproductive plant parts is an important, but not well understood, part of the yield production process in many crop plants. The objective of this research was to characterize the effects of growth stage and timing on the abortion process of soybean [Glycine max (L.) Merr.] flowers exhibiting variation in abortion. Soybean plants were grown in a greenhouse (cv. McCall) and for 3 yrs in the field (cv. Kent). The soil types were a Donerail silt loam (Typic Arguidofl), Maury silt loam (Typic Paleudalf), and a Lanton silt loam (Cumulic Haplaquolls). Fully‐opened flowers located on nodes from the middle of the main stem were marked during early (R1) and late (R3) flowering and then observed for 2 or 3 weeks to determine the extent and timing of flower abortion. Defoliation and three different depodding treatments were used to alter abortion. Nineteen percent of the early flowers aborted (failed to produce seed bearing pod) in the greenhouse, but 31 to 48% aborted over yrs in the field. Abortion of late flowers varied from 76 to 92% in two greenhouse experiments and from 69 to 90% in the three field experiments. The abortion process occurred more rapidly in the greenhouse where much of the abortion was apparent by 6 days after flower opening (DAFO), compared with the field where less than 50% of the abortion was apparent by 10 DAFO. The three depodding treatments decreased and defoliation increased flower abortion. Removing all pods from a plant except those at one node, reduced late flower abortion at that node from 69 to 54%. However, removing all pods from only one node of the plant reduced abortion at that node from 69 to 36%. The results of these experiments suggest that the processes controlling abortion operate at the individual node level and that the whole plant source‐sink ratio is of secondary importance.

Genotypic and Environmental Variation of Lag Period of Pod Growth in Soybean

“…2, T able 2) . Hei tholt et al ( 1986) reported tha t the accu mula tion of dry matter in the pod was slower in Kent (M aturity group: [V) than in M cCall (M atu rity group: 00). Umezaki ( 1991) recorded a great variation in the timing of pod lo rm ation among cultivars within the same maturity gro up.…”

Effects of shading on spatial distribution of flower and flower abscission in field-grown three soybeans in Northern China

“…The node location of a flower in soybean main axis determines, in part, when it develops. This time of a flower developing is a critical factor in determining it survival or abscission, because at individual node, the abortion of early developing flowers always had lower than those developing later (Brun and Betts, 1984;Heitholt et al, 1986).…”

Effects of Source/Sink Ratio and Cytokinin Application on Pod Set in Soybean

“…By reducing this abortion, we might be able to increase pod and seed numbers, thereby increasing the yield (Kokubun, 2004). Many previous studies have focused on two possible factors that might be involved in regulating the abortion; availability of photoassimilate or nutrients (Brevedan et al, 1978;Antos and Wiebold, 1984;Brun and Betts, 1984;Heitholt, 1986aHeitholt, , 1986b and quantity of certain hormones (Huff and Dybing, 1980;Heindl et al, 1982;Spollen et al, 1986aSpollen et al, , 1986bCarlson et al, 1987;Yarrow et al, 1988;Kokubun and Honda, 2000).…”