Effects of geoclimatic factors on the variability in Pinus pinea cone, seed, and seedling traits in Turkey native habitats

Background Stone pine (Pinus pinea L.) is harvested for its edible kernels. It is an important forest tree species, and also plays an important role in afforestation. Successful afforestation activities strongly depend on the quality of seeds and seedlings. Five eastern native populations of stone pine were analyzed, in terms of their geographical and climatic parameters, in order to identify their cone, seed, pine nut, and seedling traits. With this regard, we aimed to contribute to the reforestation, yield, and breeding of this species. Results All native populations occur in the sub-humid bioclimatic zone, according to Emberger’s bioclimatic classification, ranging 74.7–63.2 of Emberger’s Q Index value (Q), which synthesizes humidity and temperature, with lower values indicating more arid conditions. With regard to geographical factors, altitude was found to have the greatest effect on cone diameter and seed weight, while there was a weak correlation of cone, seed, and pine nut dimension with longitude and latitude. In terms of climatic factors, Q and mean of the maximum temperature of June, July, and August (ME) were found to be the main drivers behind significant effects in cone, seed, and pine nut morphometric traits. The most negative effect on seed number cone−1 (r: − 0.897), pine nut number cone−1 (r: − 0.923), pine nut yield (r: − 0.903), and pine nut weight (r: − 0.878) was Q, whereas cone diameter, seed length, and seed weight were positively correlated with the ME (r: 0.939, r: 0.889, and r: 0.866, respectively). Cone and seed diameter and seed weight increased with decreasing summer drought index (r: − 0.806, r: − 0.846, and r: − 0.866, respectively). Rainfall in the June of the third year prior to harvest time (RJ) had a negative effect on the percentage of sound seeds per cone. Annual rainfall in the third year prior to harvest time (AR) significantly affected pine nut weight (r: 0.889), although rainfall during summer had a negative effect. The empty seed ratio of the different populations ranged from 20 to 68%, while considering all populations, the empty seed ratio was 46%. Conclusions The study suggests that the Q Index and ME should be taken into account to determine cone to pine nut yield. With this regard, plantations of stone pine should be established on sub-humid areas and Q values should not exceed 75.

Pollination success and full seed percentage in European larch (Larix decidua MILL.)

A relationship between the success of pollination and the percentage of full seeds of European larch (Larix decidua MILL.) was studied using several models of non-linear correlation analysis. Although the proportion of pollinated ovules was high in most cases (especially in the middle parts of open-pollinated conelets), the mean percentage of full seeds was extraordinarily low (after the controlled self-pollination even close to zero) and most of the calculated correlation coefficients are lower than the corresponding critical value. This fact gives an evidence for the strong effect of additional important factors causing the empty seed formation in Larix even after the successful pollination of ovules.

Interactive effects of temperature, carbon dioxide and watering regime on seed germinability of two genotypes of Arabidopsis thaliana

We examined the combined effects of temperature, carbon dioxide (CO2) and watering regime during seed maturation on subsequent germinability and total phenolics of Arabidopsis thaliana [wild-type (WT) and abi1-1 mutant] seeds. Mature seeds were collected from plants that were grown under lower (22/18°C, 16 h light and 8 h dark) or higher (28/24°C, 16 h light and 8 h dark) temperatures, at ambient (400 μmol mol–1) or elevated (700 μmol mol–1) CO2 concentration, and well-watered or water-stressed. Germinated and non-germinated (viable, rotten and empty) seed percentages, germination rate and total phenolics were determined for both genotypes. Higher maturation temperatures increased seed germination percentage, but decreased germination rate, percentage of rotten and non-germinated viable seeds, and total phenolics. Elevated CO2 increased seed total phenolics. Water stress decreased the percentage of non-germinated viable seeds. Neither of the two latter factors affected other measured parameters. Seeds of the abi1-1 mutant had higher total phenolics. The fate of seeds was mostly affected by higher temperatures and water stress. Also, seeds of the abi1-1 mutant had higher germination rate, empty seed percentage and total phenolics than seeds of the WT genotype. Germination percentage was highest for the WT seeds that matured on the water-stressed plants that were grown under higher temperatures at ambient CO2. It can be concluded that higher temperatures had highest effects on seed germinability and other parameters, and elevated CO2 did not alleviate the negative effects of higher temperatures on seed viability.

Seedcorn maggot, Delia platura (Meigen) (Insecta: Diptera: Anthomyiidae)

The seedcorn maggot is a polyphagous pest, affecting more than 40 different host plants. It is an important pest of germinating soybeans and corn, and also attacks a wide range of horticultural crops including beans, peas, cucumber, melon, onion, pepper, potato, and other vegetables. Seedcorn maggots damage newly planted seeds by feeding on seed contents, often leaving empty seed shells and preventing germination. Although usually no more than 2% of the seedlings get infested by this insect, 30% to 60% plant loss may occur in the field. This 5-page fact sheet was written by Harsimran Kaur Gill, Gaurav Goyal, and Jennifer L. Gillett-Kaufman, and published by the UF Department of Entomology and Nematology, July 2013. http://edis.ifas.ufl.edu/in1002

Olive Seed Germination and Initial Seedling Vigor as Influenced by Stratification Treatment and the Female Parent

The germination of seeds and the growth of the generated plant are two phases of great importance in an olive breeding program. In this work, three stratification treatments and five cultivars (Hojiblanca, Manzanilla Cacereña, Manzanilla de Sevilla, Toffahi, and Uovo di Piccione) used as female parents in a breeding program for table olive were evaluated along two years to improve germination protocols. The stratification treatments affected seed germination (percent seeds with radicle), radicle length, seedling emergence (percent emerged hypocotyls), and the average time of emergence. The cultivars have shown great variability with respect to the requirements of the seeds and seedling growth performance. None of the treatments with heat application (25 °C) after chill (14 °C) improved the percentage of germinated seeds and seedling emergence in any year compared with the control treatment (30 days at 14 °C). Cultivars such as Manzanilla de Sevilla and Toffahi seem to be a good choice of female progenitors to improve emergence rates and to obtain early vigorous progenies, a character that has been related to a shorter juvenile period of the seedlings. Moreover, in these progenies, a clear lower apical dominance was found from the first stages of seedling growth. The olive fruit and seed traits were also influenced by the female parent. In fact, ‘Hojiblanca’ and ‘Uovo di Piccione’ showed a higher number of empty seed fruits and double seed fruits compared with the other studied cultivars.

Design and Experiment of the Pneumatic Plate-Type Vegetable Seeder

Structure plan of a new type of pneumatic plate-type vegetable seeder was put forward, and virtual prototype of the seeder was established in the paper. By kinematics simulation and analysis, L-shape arm length and minimum distance between metering device and cell plug tray were optimized. The machine control system and air pressure switch system were designed in detail. Results of orthogonal test show that, the main influence factor for single-seed rate and empty-seed rate is sowing efficiency, the second is diameter of suction hole, next is relative pressure, the minimum is interaction between those factors. The main influence factor for multi-seed rate is diameter of suction hole, the second is relative pressure, next is interaction between factors, the minimum is sowing efficiency. The best seeding effects can be achieved under the condition of 0.9 mm suction hole diameter, -4.5 kPa relative pressure, and 200-tray per hour sowing efficiency. The single-seed rate can be up to 93.59%, the empty-seed rate is 1.25%，and the multi-seed rate is 5.16%。

Effect of Boron Foliar Application on Reproductive Growth of Sunflower (Helianthus annuusL.)

A study was carried out to determine the response of open pollinated sunflower (Helianthus annuusL. cv. Shumos) to boron fertilizer. Spring and autumn grown plots were sprayed with boron (0, 50, 100, 150, 200, and 250 mg L−1) in a randomized complete block design. The results showed that boron and green Leaf area/LAI measured at the end of seed filling were linearly related in the spring crop. In the autumn crop, the relationship between boron and dry matter yield was linear, and applications above 100 mg L−1significantly increased dry matter compared to the control. For the autumn crop, 100, 200, and 250 mg L−1significantly increased seed number compared to the control, but only the 150 mg L−1treatment increased seed weight significantly. Boron tended to decrease the empty seed percentage, and for the spring crop, this was incremental and linear with applications above 150 mg L−1leading to significant reductions in empty seed percentage. Seed yield increased linearly in the autumn crop in response to boron, and 200 and 250 mg L−1applications gave significant increases in yield compared to the control.

(428) Seed Threshing and Cleaningin Flowers

Flower seed threshing and cleaning are challenging because many flowers have tiny seed, e.g., the 1000-seed weight of Begonia is 0.01 g, and others have odd-shaped seed, e.g., Tagetes has pappus-bearing seed and Fibigia has winged seed. There is a lack of information on the threshing and cleaning of flower seeds. At the Ornamental Plant Germplasm Center, a small-plot grain belt thresher was modified by disengaging its winnower and a special chute installed to collect the threshed seed and chaff together for cleaning. A custom-made threshing board is used for small samples. The seed with chaff is passed through screen with mesh size that allows all the seed to pass through so that the big pieces of chaff are retained and separated, i.e., scalping. Accurate selection of the next scalping screen (SS) is critical so that the mesh size is just right for at least 95% of the seed to pass through to remove all the chaff larger than the seed. The seed is then sieved on a grading screen (GS) of mesh size that retains at least 95% of the seed to remove all the chaff smaller than the seed. A seed blower is used to further separate the remaining chaff and empty seed based on weight and surface area by adjusting the blowing velocity (BV). A vibratory separator (VS) is used for species with round seed, e.g., Antirrhinum. An X-ray machine is used to monitor the cleaning process. The SC, GS, BV, and VT are given for Agastache, Anisodontea, Antirrhinum, Aquilegia, Aster, Astilboides, Begonia, Belamcanda, Bergenia, Cleome, Coreopsis, Dianthus, Eupatorium, Gaillardia, Geranium, Gypsophila, Iris, Lilium, Lysimachia, Myosotis, Nothoscordom, Oenothera, Passiflora, Penstemon, Petunia, Platycodon, Ranunculus, Rudbeckia, Silene, Stokesia, Synnotia, Tagetes, Talinum, Thalictrum, Verbena, Veronica, and Zinnia.

Seed parasitism redirects ovule development in Douglas fir

Many parasitic species of insects complete their entire development in seeds. They feed off storage reserves within the ovule. These reserves only normally accumulate in fertilized ovules. Consequently, female insects that oviposit their eggs directly into the plant ovule need to be able to select correctly, as unfertilized ovules of conifers normally become so-called empty seed. We provide clear evidence that in conifers, seed-parasitizing insects do not need to discriminate between fertilized and unfertilized plant ovules when ovipositing their eggs. A host-specific insect, the chalcid Megastigmus spermotrophus Wachtl (Hymenoptera: Torymidae), lays its eggs in ovules of Douglas fir ( Pseudotsuga menziesii (Mirbel) Franco) before fertilization has taken place in the plant. Oviposition not only prevents the expected degeneration and death of unfertilized ovules, but it induces energy reserve accumulation. Ovules that would otherwise develop as empty seed are redirected in their development by the insect to provide food for the developing larvae. Instead of the insect exploiting normal events during seed development, the insect manipulates seed development for its own reproductive advantage.