The effect of iprodione on the seed-borne phase of Alternaria brassicicola

Alternaria brassicicola infection of Brassica oleracea seeds was effectively controlled by a dust application of iprodione (Rovral 50% w.P.). At 2.5 g a.i./kg the seed-borne fungus was usually eliminated from samples with up to 61.5% affected seeds (35.5% internally diseased) but higher levels of infection required increased doses for complete eradication of the fungus. The germination of healthy seeds, including samples from 7–yr-old stocks, on filter paper was unaffected by the treatment. However, the germination of diseased samples, particularly those internally infected with A. brassicicola, was improved. More seedlings emerged from iprodione treated than from untreated seeds in glasshouse soil but the differences were not significant. The application of gamma-hexachlorocyclohexane to iprodione treated seeds sown in soil did not adversely affect subsequent emergence or disease control. Disease control was maintained and germination was not affected by the treatment when treated infected seeds were stored for 2 yr at 10 °C, 50% r.h. In a field trial iprodione seed treatment reduced seedling infection in a cabbage crop grown from naturally diseased seeds (100% contaminated, 45.5% internally infected) from 5.6 to 0.04%.     

The effect of seed, furrow and stem base spray treatment with iprodione on white rot disease (Sclerotium cepivorum) in spring-sown salad onions

Seed treatment with iprodione at 125 and 150 g a.i./kg was superior to calomel seed treatment at 500 g a.i./kg in reducing disease losses and increasing yields in field experiments with salad onions infected with white rot; iprodione at 50, 62·5 and 100 g a.i./kg and thiophanate-methyl at 150 g a.i./kg were as effective as calomel. Furrow treatment with iprodione or thiophanate-methyl at 0·05 and 0·15 g a.i./m row or calomel at 0·5 g a.i./m row gave similar control as equivalent rates of seed treatment. Neither seed nor furrow treatments gave adequate control with prolonged exposure of the crop to the disease. A single stem base spray of iprodione at 0·0625 g a.i./m row applied 5 wk after drilling, reduced losses from 46% with a standard calomel seed treatment to 20%; increasing the stem base spray concentration to 0·25 g a.i./m row did not improve the control but resulted in a doubling of yields. The most effective control was obtained with iprodione applied as a seed treatment at 62·5 g a.i./kg combined with a single stem base spray at 0·0625 g a.i./m row 5 wk after drilling and this reduced losses to 6% compared with losses of 46% with calomel treated seed and 88% with untreated seed; increasing the stem base spray concentration did not improve control but resulted in higher yields.     

The effect of seed and stem base spray treatment with iprodione on white rot disease (Sclerotium cepivorum) in autumn-sown salad onions

Iprodione applied to seed at 250 g a.i./kg controlled white rot in autumn-sown salad onions until July the following year, and reduced losses during the winter caused by Botrytis spp. At 25–150 g a.i./kg seed, iprodione controlled autumn and spring infections but it was less effective later in the summer. Treatment of autumn-sown onions at 50 g a.i./kg seed followed in March by a single stem base spray at 0.031 g a.i./m row (total rate c. 2.4 kg a.i./ha) gave complete control; seed treatment at 25 g a.i./kg followed by a stem base spray at 0.125 g a.i./m row (c. 4.5 kg a.i./ha) was equally effective. Four stem base sprays of iprodione at 0.075 g a.i./m row/spray (9 kg a.i./ha) applied in spring to plants raised from untreated seed, controlled spring and summer infections but yields were low because of losses caused by infection in the previous autumn. A single stem base spray of iprodione at 0.125 g a.i./m row applied in spring to plants raised from thiophanate-methyl treated seed at 125 g a.i./kg gave complete control and high yields.     

CHANGES IN THE CONTENT OF GIBBERELLIN-LIKE SUBSTANCES IN RIPENING SEED AND POD OF LUPINUS LUTEUS

The amount of gibberellin-like substances in seed, pod, embryoand "endosperm" of Lupinus luteus in relation to their developmentwas studied by means of the rice seedling test. The amount of gibberellin-like substances per seed increasedremarkably at the first stage of development, when the growthof seed and pod was very slow, and attained its maximum at suchan early stage as the dry weight of seed reached a value ofonly 10 per cent and that of pod 28 per cent of their respectivemaximum levels. Changes in amount of gibberellin-like substancespresent in the pod were very closely related to the changesin growth of pod. Gibberellin-like substances equivalent to0.3 µg gibberellin A₃ per seed and 0.028 µg perpod were found at the 20th day after anthesis, and no activityin mature seed and 0.09 µg per pod at the 50th day. Noactivity was found in the embryo itself at all stages, indicatingthat the gibberellin-like substances in seed occur only in the"endosperm," i.e. in the tissues that will eventually form testain fully ripened stage. (Received December 18, 1962; )     

Seed Development in Phaseolus vulgaris L. cv Seminole: I. Developmental Independence of Seed Maturation

Phaseolus vulgaris L. cv Seminole pods removed from the plant continued their development when incubated in suitable conditions. Seeds continued to grow and develop and pods and seeds passed through an apparently normal developmental sequence to dryness. Seed growth was at the expense of pod dry weight (DW) reserves. Losses of pod DW paralleled DW gains by seeds in detached pods and in pod cylinders containing a seed. The transfer activity was apparent only within the period 10 to 30 days after anthesis (DAA) with maximal activity between 15 to 20 DAA. This period corresponds to maximum pod growth and the attainment of maximal DW. Seeds are in only the early phase of seed growth at this time. No DW transfer was observed at developmental stages beyond 30 to 35 DAA when normal senescence DW losses in pods became evident and seeds were in the later phase of seed fill. Pods or pod cylinders remained green and succulent over the transfer period, later passing through yellowing and drying phases characteristic of normal development. DW transfer was dependent on funicle integrity and was readily detectable in pod cylinders after 7 days incubation. The DW transfer activity may contribute to continuing nutrition of seeds under conditions where the normal assimilate supply to seeds becomes limiting. Defoliation and water stress treatments applied to Phaseolus plants reduced seed yields but allowed persistence of seed maturation processes such that all seeds developing to dryness were capable of germination.     

Regulation of monocarpic senescence of Brassica campestris by the developing pods

Senescence of Brassica campestris L. cv. B-9 was studied with regard to seed maturation and source-sink relationships. In normal control plants leaf senescence (as determined by the change in chlorophyll level) started and proceeded in a progressive manner from base to apex during the period of early pod setting. Complete yellowing of the leaves occurred well before the seed maturation and pod wall senescence. The pod wall always senesced before the attainment of final seed weight. In two different sets of acrocarpous plants containing 65 pods and 10 pods, respectively, leaf senescence was delayed during the pod filling period. It started non-sequentially after complete yellowing and senescence of the pod wall. The degree of leaf senescence at the post-pod filling stage was almost proportional to the number of pods present. When peduncles of the acrocarpous 10-podded plants were removed after the pod filling stage of the plant, leaf senescence was delayed compared to plants whose pedicels were removed, although the senescence pattern of the upper three leaves was nonsequential in both cases. Defruiting at an early stage of development delayed leaf senescence, although the pattern of such senescence remained unaltered (i.e. nonsequential). Defoliation hastened the seed-filling process and pod wall senescence. Plants containing fewer pods had higher average seed weight, although yield per plant was reduced.
These results suggest that the pod wall serves as a temporary as well as intermediary storage organ and that foliar senescence is not directly related to seed maturation. The possible cause of uncoupling between foliar senescence and seed development is discussed.     

影响菜豆普通花叶病毒种子传毒的因素

研究了影响菜豆普通花叶病毒(BCMV)种子传毒的一些因素,不同品种,不同感染时期种子的传毒率有显著差异,苗期感病的植株,不同荚位的种子传毒率是:下部>中部>上部,花期感病者则是:中部>上部>下部,感病植株的斑驳荚种子传毒率,依品种的不同,比无斑驳荚者高3.2～9.3倍。     

The effect of elevated temperatures and their duration on the incidence of hollow heart in pea seeds

Plants of Pisum sativum cv. Pania were exposed to high temperature (35 ^oC day/25 ^oC night) at three stages in development. These were: (i) at process crop maturity, when the seed moisture content (m.c.) was 80%, i.e. about 10 days prior to pod wrinkle, (ii) at a seed m.c. of 70 to 80%, about the onset of pod wrinkle, and (iii) when the seed m.c. was 50 to 60%, 10 days after the onset of pod wrinkle. At each stage of development the high temperature treatment was imposed for 2,4,6, 8 or 10 days. Plants exposed to high temperature at seed m.c. of 70 to 80% produced seed with the highest incidence of hollow heart and at all stages of development the incidence increased with the length of exposure to the high temperature. Where plants at the development stage of pod wrinkle (seed m.c. 70–80%) were exposed to a range of temperature regimes for 5 days, over 20% of the seeds had hollow heart when the mean day/night temperature was 25 ^oC. Above a mean temperature of 25 ^oC, the percentage of affected seed increased with increasing day or night temperature. Over 80% of the seeds had hollow heart symptoms after 5 days exposure to a daily mean temperature of 32-5 ^oC. The severity of symptom development was not related to the proportion of seeds with the disorder and, under laboratory conditions, seed germination was not affected.     

甘草野生种群果实与种子形态特征的地理变异研究

目的：研究甘草荚果和种子形态特征地理变异规律并分析其形成的生态学机制。方法：采用样方调查的方法测定全国4省区8个旗县甘草野生种群的地上植株形态特征,采用双重筛选逐步回归分析方法探讨甘草荚果和种子形态特征的地理变异规律及其形成的生态学机制。结果：（1）不同甘草种群的荚果数、荚果腺毛长度、种室数目、每荚种子粒数和结实率5项指标的差异达到了极显著水平（P〈0．01）;荚果长度、荚果厚度、荚果腺毛密度和种子长度4项指标的差异达到了显著水平（P〈0．05）。（2）荚果厚度、种室数目等5项形态特征与经度呈显著相关,只有荚果腺毛长度1项指标与纬度显著相关。结论：甘草野生种群荚果与种子形态特征存在显著的地理变异,其变异趋势以经向变异为主,光照因子差异是导致地理变异的主要原因,其次为温度因子和水分因子,其相关关系可用多元回归模型解释。     

Pattern of dry matter accumulation in developing fruit parts of early- and late-maturing pigeon peas (Cajanus cajan (L.)Millsp.)

Pigeon pea cultivars AL 15 (early-) and T₂₁ (late-maturing) were compared for dry matter accumulation in fruit parts pod wall (PW), seed coats (SC) and seed at various seed developmental stages. Significant water loss and dry matter accumulation in the fruit parts commenced much earlier in cv. AL 15 as compared with cv. T₂₁. The pod wall accumulated starch, reducing sugars and N-substances up to 21 and 28 days after anthesis (DAA) in cultivars AL 15 and T₂₁, respectively, which was later distributed to the seed. Growth of pod wall and seed was sequential, not concurrent, as the pod wall lost significant dry matter when the seeds within them reached their maximum dry matter. The fruit parts of cv. AL 15 accumulated more photosynthates than cv. T₂₁ at all comparable stages.     

Effects of decreasing source/sink ratio in soybeans on photosynthesis, photorespiration, transpiration and yield

Abstract. Shading of all side leaflets of a determinate soybean cultivar during pod filling significantly increased rates of photosynthesis in the unshaded centre leaflets, compared to centre leaflets of controls. Higher rates were associated with both higher stomatal and mesophyll conductances, and were reversible within 2 days when shades were removed. These higher rates of photosynthesis were not associated with decreased percentage enhancement by low oxygen, indicating that treatment effects were probably not associated with changes in photorespiration relative to photosynthesis. Percentage enhancement did, however increase as the plants approached physiological maturity, chiefly because of a decrease in photosynthesis.
In spite of these increases in rates of photosynthesis seed weight per plant was decreased by 37% in plants with side leaflets shaded for the entire pod-filling period and by 28% in plants shaded for only the second half of the period. In plants where shades were removed during the second half of pod filling seed yield was reduced by only 19% because shade removal delayed leaf senescence. The four treatments reduced yield by different mechanisms. Plants shaded continuously during pod filling produced fewer seeds than controls, but the weight per seed was similar. When shading was applied during the second half of pod fillings seed number was unchanged but weight per seed was significantly reduced. In contrast when shades were removed for the second half of pod filling, seed number remained similar to that of continuously shaded plants, but seed weight increased.
Although all shading treatments reduced yield, the reduction was not proportional to the 63% reduction in leaf area available for photosynthesis. This was because (1) photosynthetic rates in the centre leaflet of shaded plants were higher than rates in controls, (2) stem and lower surface photosynthesis in shaded leaf-lets contributed to whole leaflet photosynthesis.     

Canavanine distribution in jackbean fruit during fruit growth

Summary Canavanine is an arginine analogue found in the seeds of many common legumes and is known to inhibit protein synthesis and growth in a number of organisms. Yet canavanine may comprise as much as 4% of the seed dry weight of the jackbean (Canavalia ensiformis).Canavanine is accumulated during earlier development in the pod, but disappears upon ripening. A corresponding increase in seed canavanine of about the same magnitude as the loss in the pod takes place during this latter time, but there is a subsequent significant increase of canavanine content of the seed after all detectable canavanine has disappeared from the pod. The first of these changes suggests synthesis of canavanine in the pod and transport into the seeds while the second one indicates a synthesis of canavanine in the seeds themselves, or possibly in the leaf or pod with rapid translocation to the seed.Canavanine was found to be at its highest concentration in the seed coats and pods when they were growing most rapidly and to gradually decline afterwards; however, the canavanine concentration of the seeds was found to be constant throughout fruit development.The pattern of canavanine mobilization in jackbean fruits was quite similar to the known pattern of total nitrogen mobilization typical of other leguminous fruits. This is consistent with a role as a nitrogen transport and storage compound.University of Tennessee, Department of Botany, Contribution N. Ser. No. 279.     

Physical restriction of pods causes seed size reduction of a brassinosteroid-deficient faba bean (Vicia faba)

BACKGROUND AND AIMS: A brassinosteroid-deficient mutant faba bean (Vicia faba 'Rinrei') shows dwarfism in many organs including pods and seeds. 'Rinrei' has normal-sized seeds together with dwarf seeds, suggesting that dwarfism in the seed may be indirectly caused by brassinosteroid deficiency. The mechanism of seed size reduction in this mutant was investigated. METHODS: The associations between seed orientation in the pod, seed numbers per pod and pod lengths with seed sizes were analysed in 'Rinrei' and the wild-type plant. KEY RESULTS: 'Rinrei' seeds are tightly arranged in pods containing two or three seeds. Seed size decreased as the number of seeds per pod increased or as the length of the pod decreased. Where no physical restriction occurred between seeds in a pod, the wild-type faba bean seeds had a nearly constant size regardless of seed number per pod or pod length. 'Rinrei' seeds in pods containing single seeds were the same size as wild-type seeds. Brassinolide treatment increased the seed size and the length of pods containing three seeds in 'Rinrei'. CONCLUSION: Seed size of 'Rinrei' is mainly regulated through a reduction of pod length due to brassinosteroid deficiency; physical restriction within pods causes a reduction in seed size. These results suggest a possible mechanism for increasing faba bean yields to optimal levels.     

A model to predict seed number per pod from early pod growth rate in pea (Pisum sativum L.)

Seed number per pod in pea is variable. After fertilization,any number of ovules may abort in the pod. This paper describesan analysis of the relationship between pod growth and seedabortion rate. Pod dry weight was highly correlated to pod lengthbefore the final stage in seed abortion. By measuring pod lengthduring the period of seed formation and counting the seeds inthe same pods at the end of this period, we show that seed numberper pod was correlated with early pod elongation. From thesedata we propose and test a model for predicting seed numberper pod from early pod elongation rates. Key words: Pea, pod length, pod growth, seed number, modelling     

Effect of Macrophomina phaseolina Infection on the Physico-Chemical Components of Groundnut Seed

Various aspects of groundnut seed deterioration due to M. phaseolina infection were studied. Fungal infection caused both quantitative and qualitative damage to the seed. It resulted in characteristic discoloration of pod and kernel. There was marked reduction in the pod and kernel yield, shelling percentage and oil content. The oil extracted from healthy kernels was barium yellow, whereas, oil from diseased kernels was amber yellow in color. The diseased kernels contained lesser amounts ofstearic and behenic acids but higher quantities of palmitic, oleic, linoleic and arachidic acids. Four fatty acids, namely, lauric, myristic, palmitoleic and eicosenoic acids were absent in diseased kernels.     

Yield response of cowpea, Vigna unguiculata L. (Walp), to infestation of Aspavia armigera F. (Hem., Pentatomidae)

Abstract:  Yield-related responses of cowpea plants to artificial infestation of Aspavia armigera , at the onset of podding, at different densities, 0, 1, 2, 4, 8, 16 and 32 pairs per cage were studied on cowpea in caged pots and field plots. With increasing insect density there was a corresponding significant increase (P < 0.05) in pod and seed damage, and reduction in pod length, numbers of pods per plant and seeds per pod, seed weight and total yield. Pod production was significantly higher (P < 0.05) in infested plants than in the control; at 1- and 16-pair levels, pod production increased by 75% and 81% over the uninfested control in the pot and field experiments respectively. Then again, with increase in insect density there was a progressive high-magnitude increase in pod abortion reaching 252.6% and 200% at the 32-pair level on potted and field cowpea, respectively, resulting in drastic reductions in the number of harvestable pods. Cowpea compensation mechanism was lost completely as insect population increased. The lowest density of A. armigera at which significant reduction (P < 0.05) occurred in total seed yield compared with the control was one pair. The relationship between insect density and pod damage, and yield was best described by a quadratic + linear fit, while that between insect density and seed damage was best fit as polynomial with very high significant r -values. Chi-squared analysis showed that the models derived from pot and field data were similar.     

SEED SIZE AND SEED PACKAGING VARIATION IN BAPTISIA LANCEOLATA (FABACEAE)

Pods and seeds of field-collected Baptisia lanceolala plants were analyzed to partition seed weight and seed packaging trait variance among and within plants and to detect relationships between these traits. Packaging traits studied were: pod weight, seed weight per pod, number of seeds per pod, mean weight of seeds per pod, proportion seed weight of total pod weight, and pod weight per seed. Significant among-plant variation was found for seed weight and all packaging traits. Within plants, positive correlations were found between number of seeds per pod and pod dry weight and between the proportion seed weight of total pod weight and number of seeds per pod. Pod weight per seed was negatively correlated with number of seeds per pod. Most plants had a negative correlation between mean seed weight and number of seeds per pod. When compared with an equality of slopes test, slopes of regressions of the above pairs of traits were found to differ among plants. Among plants, the same relationships were found, except for the latter two traits, which were not correlated. These within-plant patterns may represent constraints on seed weight variance imposed by the seed package. This view is supported by a positive correlation between packaging trait variance and seed weight variance. Packaging-related constraints could have an effect on seed weight in this and other species. If these phenotypic constraints have a genetic basis, then selection on seed packaging could change seed weight in a way different from that which might be predicted by considering seed weight alone.     

Identification of QTLs for seed and pod traits in soybean and analysis for additive effects and epistatic effects of QTLs among multiple environments

Soybean seed and pod traits are important yield components. Selection for high yield style in seed and pod along with agronomic traits is a goal of many soybean breeders. The intention of this study was to identify quantitative trait loci (QTL) underlying seed and pod traits in soybean among eleven environments in China. 147 recombinant inbred lines were advanced through single-seed-descent method. The population was derived from a cross between Charleston (an American high yield soybean cultivar) and DongNong594 (a Chinese high yield soybean cultivar). A total of 157 polymorphic simple sequence repeat markers were used to construct a genetic linkage map. The phenotypic data of seed and pod traits [number of one-seed pod, number of two-seed pod, number of three-seed pod, number of four-seed pod, number of (two plus three)-seed pod, number of (three plus four)-seed pod, seed weight per plant, number of pod per plant] were recorded in eleven environments. In the analysis of single environment, fourteen main effect QTLs were identified. In the conjoint analysis of multiple environments, twenty-four additive QTLs were identified, and additive QTLs by environments interactions (AE) were evaluated and analyzed at the same time among eleven environments; twenty-three pairs of epistatic QTLs were identified, and epistasis (additive by additive) by environments interactions (AAE) were also analyzed and evaluated among eleven environments. Comparing the results of identification between single environment mapping and multiple environments conjoint mapping, three main effect QTLs with positive additive values and another three main effect QTLs with negative additive values, had no interactions with all environments, supported that these QTLs could be used in molecular assistant breeding in the future. These different effect QTLs could supply a good foundation to the gene clone and molecular asisstant breeding of soybean seed and pod traits.     

Patterns of fruit and seed production inBauhinia ungulata (Leguminosae)

Patterns of seed and fruit production ofBauhinia ungulata, a small tree legume indigenous in tropical America, were studied in Costa Rica. Only about 8% of flowers produced fruits. The average pod had 19 ovules and about two thirds of these began seed development, with mature pods containing an average of 9.7 mature undamaged seeds. About half of the mature pods were damaged by herbivores and within these, 27% of ovules or seeds had been eaten. Among trees there was no significant variation in pod production, but the number of ovules per pod and seed production per pod varied significantly. Within infructescences most pods were retained at middle positions. Within pods, the probability of an ovule developing into a seed increased toward the distal end. The pattern of seed and fruit production in this species agrees well in general with that reported for other neotropical legumes. The abortion of seeds and fruits can be regarded as a way of controlling maternal investment, and as a response to herbivory.     

Density Studies on Lupins. II. Components of Seed Yield

Components of seed yield of cv. Ultra (Lupinus albus L.) andcv. Unicrop (L. angustifolius L.) were measured when grown atthree densities. The low density (10 plants m^–2) Unicropyield (34 g seed per plant) was 1.8 times that of Ultra as ithad more branches, pods and seeds per pod. Ultra seeds (310mg per seed) were heavier than Unicrop seeds (180 mg). The branchingpattern of Ultra was less dependent on plant density, henceat 93 plants m^–2 it gave a higher per plant yield (7.4vs 6.4 g) than Unicrop at lower densities (83 plants m^–2).Density had most influence on pod formation and only small effectson seeds per pod and seed weight. Yield components on the main-steminflorescence were influenced less by density than componentson branch inflorescences. Later formed, higher order generationsof inflorescences were most affected by increased inter- andintra-plant competition. Pod numbers on the main-stem were similarfor both species. Pods formed at higher flower nodes in Unicrop,but the lower flower nodes were less fertile than those in Ultra.Node position of flowers had no influence on seed set in main-stemUnicrop pods, but pods from higher nodes in Ultra formed fewerseeds. Seed weights in Unicrop were similar among main-stemnodes but in Ultra seed weights tended to increase at highernodes. Lupinus spp, lupins, seed yield, planting density