Assessment of Soybean Resistance Level to Pod Sucking Bug Riptortus linearis F. (Hemiptera: Coreidae) based on No-choice and Free-choice Tests

Background: The infestation of the pod sucking bug Riptortus linearis is one of the limiting factors of soybean productivity in Indonesia. The research aims were to identify the level of resistance to the pod sucking bug R. linearis on several soybean genotypes based on the no-choice test (NCT) and free-choice tests (FCT). Methods: The genetic materials used were 49 soybean genotypes. The study was conducted in the Indonesian Legumes and Tuber Crops Research Institute (ILETRI) from August to December 2020, using the randomized block design in triplicates. The evaluation for pod sucking bug resistance was based on NCT and FCT. Result: The FCT resulted in two genotypes with a consistent moderately resistance level (20-40% of damage intensity) to pod sucking bug based on the pod and seed damage intensity. The NCT method resulted in five genotypes as moderately resistant (20-40% of damage intensity) to pod sucking bug based on the seed damage. The NCT resulted in higher average intensity of pod and seed damage (80.25% and 71.23%, respectively) than the FCT (69.91% and 69.09%, respectively). Two soybean genotypes (Degra/Anjasmoro-1-559 and Anjasmoro/IAC100-2-618) with a consistent moderately resistance level could be used for cultivar improvement in the breeding program. The pod trichome density was suggested to be one of the effective morphological defenses against the pod sucking bug attack.

Multivariate analysis on blackgram genotypes for bruchine (Callosobruchus maculatus F.) resistance towards selection of parental lines

Black gram (Vigna mungo (L.) Hepper) is one of the most important pulse crops in daily diets. However, black gram production and post-harvest preservation are still tedious due to the losses caused by the storage pest bruchine, Callosobruchus maculatus (F.), both quantitatively and qualitatively. Hence, the present study involves the utilization of the multivariate analysis by effectively understanding variation among the genotypes based on their level of bruchine infestation. The multivariate studies indicated that the traits viz., the total number of adult emergence (AE), seed damage % (SD) and seed weight loss % (SWL) had more variation and with more significant correlation among them. Also, these traits are the most influential principal component traits governing 88% of the variation among genotypes. The divergence analysis showed that the genotype TU 68 found in cluster II would have the potential to create the variation for bruchine infestation among the black gram genotypes involved in the study. As it has scored lesser adult emergence (AE) (7 adults), seed damage % (SD) (14 %) and seed weight loss % (SWL) (17.79 %) than the other genotypes. It shows the resistant nature of the genotype against bruchine beetles. Hence, TU 68 could be utilized in the future hybridization programme as a donor for bruchine resistance.

Biotic and Abiotic Interactions Shape Seed Germination of a Fire-Prone Species

Both biotic and abiotic environmental filters drive the occurrence, distribution, and persistence of plant species. Amongst drivers that influence the distribution of plants in harsh environments, seed predation and temperature are particularly important in habitats that are prone to fire. In this study, we highlight the combined effects of predation and high temperature simulating fire to understand its effects on the germination percentage and germination speed of the fire prone species Copaifera oblongifolia. Groups of seeds attacked by the beetles Rhinochenus brevicollis and Apion sp., seeds manipulated by the ant Atta laevigata, and seeds left intact were put to germinate in controlled environments. To evaluate the effects of abiotic filters, seeds with intact elaiosomes and seeds with elaiosomes removed by the ant Atta laevigata were exposed to temperatures of 27, 60, 100, and 200 °C. The results showed that only 2.8% of the seeds attacked by R. brevicollis germinated. Seeds attacked by Apion sp. germinated faster, followed by seeds with their elaiosomes removed and seeds with intact elaiosomes. Seeds attacked by Apion sp. had the lowest germination percentage. The temperature of 200 °C killed seed embryos, whereas seeds exposed to 100 °C took longer to germinate than seeds exposed to other temperatures. Our results reveal that fire intensity and seed damage are important drivers of seed germination of C. oblongifolia.

REDUCING SEED DAMAGE IN THE RAW COTTON SEPARATOR

The article discusses the design features of the CX cotton separator. As a result of the analysis, the main reasons are established that lead to increased mechanical damage to seeds, and, as a consequence, to a decrease in the quality of products of the cotton ginning industry. The modernisation of the existing design of the separator is proposed by installing a visor at the outlet of the air flow into the separating chamber. On the basis of experimental studies, a regression mathematical model was obtained, which made it possible to assess the influence of the main design and technological parameters on the mechanical damage of seeds. It was found that this parameter, in addition to the position of the visor, is significantly influenced by the air flow rate at the entrance to the separation chamber and the separator performance. Recommendations on the choice of the position of the visor are obtained.

Reactions of Some Varieties of Pearlmillet, Pennisetum glaucum (Linn.) R. Br. emend Stuntz. to Rice Moth, Corcyra cephalonica Staint.

Ten varieties of pearlmillet (RHB-173, RHB-177, MPMH-17, HHB-67, Pro Agro-9450, Pro Agro-9001, Pioneer 86 m 86, Pioneer 86 m 84, Pioneer 86 m 38 and Raj-171.) were evaluated for reaction to Corcyra cephalonica Staint. in the laboratory conditions. The adult emergence (F1), weight losses and susceptibility index in these varieties were ranged from 9.33-32.00, 10.44–31.69% and 2.77–6.82, respectively, the minimum in Pioneer 86 m 86 and maximum in Raj-171; other varieties were in the middle order. The seed damage recorded in different varieties ranged from 23.67–75.84%, the minimum in Pioneer 86 m 86 (23.67%), Pro Agro-9450 (25.55%) and Pro Agro-9001 (28.33%), these treatments were found at par each other. The Raj-171 was found to be badly infested (75.84% grain damage) which differed significantly over other varieties. The developmental period of the pest varied from 50.88–80.61 days in different varieties, minimum being in Raj-171 and maximum in Pioneer 86 m 86.

Reactions of Some Varieties of Pearlmillet, Pennisetum glaucum (Linn.) R. Br. emend Stuntz. to Rice Moth, Corcyra cephalonica Staint

Ten varieties of pearlmillet (RHB-173, RHB-177, MPMH-17, HHB-67, Pro Agro-9450, Pro Agro-9001, Pioneer 86 m 86, Pioneer 86 m 84, Pioneer 86 m 38 and Raj-171.) were evaluated for reaction to Corcyra cephalonica Staint. in the laboratory conditions. The adult emergence (F1), weight losses and susceptibility index in these varieties were ranged from 9.33-32.00, 10.44-31.69% and 2.77-6.82, respectively, the minimum in Pioneer 86 m 86 and maximum in Raj-171; other varieties were in the middle order. The seed damage recorded in different varieties ranged from 23.67-75.84%, the minimum in Pioneer 86 m 86 (23.67%), Pro Agro-9450 (25.55%) and Pro Agro-9001 (28.33%), these treatments were found at par each other. The Raj-171 was found to be badly infested (75.84% grain damage) which differed significantly over other varieties. The developmental period of the pest varied from 50.88-80.61 days in different varieties, minimum being in Raj-171 and maximum in Pioneer 86 m 86.

Performance Evaluation of a Melon Shelling Machine with Different Power Sources

Performance evaluation of an electric motor and a fuel-engine powered machine used for shelling melon seeds was performed in this study to determine the effects of shelling speed and moisture content on machine productivity. The melon seeds used for the evaluation of the existing melon shelling machine were sourced locally from Umungasi market in Aba, Abia state, Nigeria. The unshelled melon seeds as used were weighed (25g each), sprinkled with water and partially dried with natural air for 25 minutes. This enabled the skin coat became slightly softened and the cotyledon easily detached from the shell, thus making the shelling more efficient. To evaluate the parameters (machine productivity, throughput capacity and percentage seed damage), the melon seeds were employed. For the shelling performance, melon seeds of five different moisture contents (7.48, 10.24, 13.92, 18.36, 21.44%) dry basis (d.b.) at different shelling speeds (850, 1000 and 1200 rpm) were utilized in the evaluation. From the evaluation, results revealed that the machine has an optimal productivity of over 83% and percentage seed damage of 14.2% at seed moisture content of 21.44% and drum speed of 1200 rpm for both power sources. Maximum machine throughput capacity of over 940 kg/h was recorded at 1200 rpm and 21.44% moisture content for both power sources. Overall, results obtained indicated that the machine can effectively shell melon seeds and that seed moisture contents and shelling speed affected the machine productivity.Keywords— Performance operation, evaluation, motorized, melon, shelling machine

EXPERIMENT AND PARAMETERS OPTIMIZATION OF SEED DISTRIBUTOR OF MECHANICAL WHEAT SHOOTING SEED-METERING DEVICE

In order to solve problems of lower seed-filling stability and wheat seed damage of mechanical shooting seed-metering device, the filling structure of the shooting device was optimized. The effects of seed movement were obtained through analysing the kinematics and dynamics of wheat seed through seed distributor. The influence factors were the inner diameter of seed distributor, the rotational speed of seed distributor and the inclination angle of distributor window. The discrete element software (DEM) was used to simulate the motion process to explore the different factors on the wheat seeds’ movement characteristics in the shooting device. The coefficient of variation of shooting uniformity and shooting speed of wheat seed were selected as test indicators. A verification experiment was conducted, and a high-speed camera was taken to obtain wheat seed’s movement and shooting speed. The verification test showed that the constant uniform variation coefficient of seed amount and average shooting depth was 8.6% and 32 mm, respectively.

Assessment and Models of Insect Damage to Cones and Seeds of Pinus strobiformis in the Sierra Madre Occidental, Mexico

Insect damage to cones and seeds has a strong impact on the regeneration of conifer forest ecosystems, with broader implications for ecological and economic services. Lack of control of insect populations can lead to important economic and environmental losses. Pinus strobiformis is the most widespread of the white pines in Mexico and is widely distributed throughout the mountains of northern Mexico. Relatively few studies have examined insect damage to the cones and seeds of these pines, especially in Mexico. In this study, we therefore analyzed insect damage to cones and seeds of P. strobiformis in Mexico by using X-ray and stereomicroscopic analysis. The specific objectives of the study were (a) to characterize insect damage by measuring external and internal cone traits, (b) to assess the health of seeds and cones of P. strobiformis in the Sierra Madre Occidental, Mexico, and (c) to estimate the relative importance of the effects of different environmental variables on cone and seed damage caused by insects. We found that 80% of P. strobiformis seeds and 100% of the tree populations studied had damage caused by insects. Most seeds were affected by Leptoglossus occidentalis, Tetyra bipunctata, Megastigmus albifrons, and the Lepidoptera complex (which includes Apolychrosis synchysis, Cydia latisigna, Eucosma bobana, and Dioryctria abietivorella). The cones of all tree populations were affected by some type of insect damage, with Lepidoptera causing most of the damage (72%), followed by Conophthorus ponderosae (15%), the hemipteran L. occidentalis (7%), and the wasp M. albifrons (6%). The proportion of incomplete seeds in P. strobiformis at the tree level, cone damage by M. albifrons and seed damage in L. occidentalis were associated with various climate and soil variables and with crown dieback. Thus, cone and seed insect damage can be severe and potentially impact seed production in P. strobiformis and the reforestation potential of the species. The study findings will enable managers to better identify insects that cause damage to cone and seeds. In addition, identification of factors associated with damage may be useful for predicting the levels of insect predation on seeds and cones.