Tetraploid Cv Research Articles

Pollen Characteristics of Diploid and Tetraploid Grape Cultivars

For a successful grapevine breeding program, pollen viability, germination ability, and cultivar compatibility information are of vital importance. In this study, pollen viability, germination rates, pollen tube lengths, and pollen tube diameters of three grape cultivars [Kyoho (4n), Ekşi Kara (2n), and Gök Üzüm (2n)] were investigated. Pollen viability rates were determined using the IKI (iodine potassium iodide) staining test. In vitro, pollen germination rates were determined using a semi-solid medium containing 20% ​​sucrose and 1% agar. As a result, significant differences were detected in pollen viability, germination rates, and pollen tube lengths of the examined grape cultivars. The first germination started at the 48th hour in all three grape cultivars. In cv. Ekşi Kara had the highest pollen viability while the lowest (3.05%) value in terms of pollen germination was determined. Pollen tube length and pollen tube diameter of the cv. Kyoho had higher values ​​than the other two diploid cultivars. Pollen tube formation started in the first 48th hours, while pollen tube growth continued to increase until the 96th hours. As a result, it was confirmed that the flower structure of the cv. Ekşi Kara was functionally female. In suitable ecologies, diploid cv. Gök Üzüm and tetraploid cv. Kyoho were found to be usable as pollinators.

Plant-Mediated Behavioural Avoidance of a Weevil Towards Its Biological Control Agent.

New Zealand pastures largely comprising Lolium ryegrass species (Poales: Poaceae) are worth $19.6B and are subject to major pest impacts. A very severe pest is the Argentine stem weevil Listronotus bonariensis (Kuschel) (Coleoptera: Curculionidae). This has been previously suppressed by the importation biological control agent, Microctonus hyperodae Loan (Hymenoptera: Braconidae). However, this suppression has recently declined and is subject to investigation. It has been hypothesised that grass type influences the parasitism avoidance behaviour by the weevil and thus parasitism rates. This study explored the hypothesis using three common pasture grasses: a diploid Lolium perenne x Lolium multiflorum hybrid ryegrass (cv. Manawa), a tetraploid Italian ryegrass L. multiflorum Lam. (cv. Tama), and a diploid perennial ryegrass L. perenne L. (cv. Samson). The described laboratory-based microcosm methodology determined the extent of weevil avoidance behaviour on each of these three grasses when subjected to the parasitoid. Such reaction was gauged by the extent of reduced weevil on-plant presence and feeding compared to the control populations. In the absence of the parasitoid, the hybrid cv. Manawa ryegrass is as highly favoured by the weevil as the tetraploid cv. Tama. On diploid cv. Samson, feeding is considerably less. In the presence of the parasitoid, weevils on the tetraploid cv. Tama plants showed little avoidance activity in response to the parasitoid and it can be argued that the benefits of staying on this plant outweighed the possibility of parasitism. Conversely and surprisingly, in the parasitoid’s presence, weevils on diploid cv. Manawa showed very strong avoidance behaviour leading to levels of exposure similar to those found on the less-preferred diploid cv. Samson. These findings reflect how weevil parasitism rates have declined in most Lolium grasses, particularly diploids, since the 1990s, but not in the tetraploid L. multiflorum. This contribution supports the hypothesis that the decline in weevil parasitism rates has been the result of rapid evolution arising from parasitoid-induced selection pressure and the countervailing effect of the nutritional quality of the host plants.

Isolation and Culture of Pollen Tetrad Protoplasts from Solanum tuberosum

Pollen protoplasts provide a sexual and haploid system for haploid production, cell fusion and mutation studies used in plant improvement. Due to the multiploidy, heterozygosity, and often self-incompatibility in tetraploid genotypes, haploid potatoes are desirable for breeding schemes via ploidy manipulations. In this study, two tetraploid varieties and two dihaploid lines of potato were used for pollen tetrad protoplast isolation and culture. The meiotic tetrad buds were first pre-treated at 5 °C for 0–12 days, then the tetrads were transferred into enzyme solutions containing different concentrations of snailase (0.5–1.5%), 0.3 M osmolites (sucrose, mannitol, glucose or sorbitol), 1.0% Cellulose, 0.5% Hemicellulase, 0.5% Pectolyase, 0.3% Sucrose, 3 mM 2-(N-Morpholino) ethane sulfonic acid, 1% polyvinyl pyrrolidone, 0.01% casein hydrolysate and K3 medium compositions. Among the four donor materials, tetraploid cv. Gannongshu No. 3 (‘GNS No.3’) showed the greatest protoplast yield (74.6 ± 2.4%). In this variety, most of the tetrad protoplasts regenerated a cell wall and continued cell divisions were observed when they were inoculated in K3 basic medium supplemented with (0.5–1.0) mg/L 2,4-D + (0.1–0.5) mg/L KT + 0.4 mg/L 6-BA +800 mg/L glutamine +100 mg/L serine. ‘GNS No.3’ also showed the greatest first division frequency (21.6 ± 1.5%) and sustained division to form multicellular structures. The study findings suggested that cultured tetrad pollen protoplasts could reverse the gametophytic developmental pattern programmed in vivo to a sporophytic pathway leading to multicellular microspore-derived colonies.

Chromosome doubling can increase heat tolerance in Lonicera japonica as indicated by chlorophyll fluorescence imaging

Imaging fluorometry was applied to investigate the tolerance of Japanese honeysuckle (Lonicera japonica Thunb.) of different ploidy levels to heat stress. Seedlings of L. japonica, the diploid cv. Damaohua and the tetraploid cv. Jiufengyihao, were exposed to heat stress of 42 °C for 6 h and a recovery for 10 h. Heat stress significantly decreased maximum photochemical efficiency, electron transport rate, effective quantum yield of photosystem 2, and photochemical quenching of both cultivars, but it decreased the non-photochemical quenching (NPQ) only in the tetraploid. Heat stress increased the content of total soluble sugars, proline, and malondialdehyde in both cultivars while it increased NPQ only in the diploid. Our findings suggest that the tetraploid showed to be more resistance to heat stress than the diploid of L. japonica, which was indicated by different chlorophyll fluorescence imaging techniques and metabolic changes. Moreover, the degree of recovery in the tetraploid was higher than that of the diploid. The tetraploid also possessed thicker epidermis (both upper and lower) and palisade tissue as well as denser pubescence.

Phenotypic characterization and nuclear microsatellite analysis reveal genomic changes and rearrangements underlying androgenesis in tetraploid potatoes (Solanum tuberosum L.)

Two (di)haploids (2n = 2x = 24) and nine tetraploids (2n = 4x = 48) obtained from Solanum tuberosum through anther culture were characterized for nDNA variation, phenotypic variation and nuclear microsatellite polymorphism. Androgenic (di)haploids were also characterized for late blight resistance. The (di)haploid C-13 was derived from Indian tetraploid potato cv. Kufri Chipsona-2, while D4 from TPS (true potato seed) parental line JTH/C-107, which is an interspecific hybrid between Indian tetraploid cv. Kufri Jyoti and diploid (2n = 2x = 24) cultivated species S. phureja Juz. & Buk. IVP-35. C-13 and D4 (both male-fertile) could be distinguished from their corresponding tetraploid anther donors based on plant height, shoot number, terminal leaflet length and width, leaf ratio, anther length, pollen diameter and corolla width and radius. A complete reversal of flower color occurred in D4, and C-13 was highly resistant to late blight. Most interestingly, about 3–7% increase in nDNA content occurred in most of the anther-derived tetraploids. Both the androgenic (di)haploids and their anther donors had unique genotypes at the microsatellite loci POTM1-2, STM0015 and STM0019b. However, the nine anther-derived tetraploids shared the same allelic profiles with their anther donor JTH/C-107 at all the microsatellite loci, except at STM0019a where they were characterized by the absence of a standard donor allele (186-bp). A typical (di)haploid-specific allele was detected for the locus STWAX-2 where the standard donor alleles were replaced by a 230-bp allele in both C-13 and D4. The over-expression of microsatellite variation in D4 that also shows triallelic profiles at the microsatellite loci POTM1-2 and STM0015 can perhaps be attributed to its chimeric structure, which might have been formed through incomplete fusion of two different pro-embryos during the first steps of microspore division.

Optimization of Conditions for In vitro Pollen Germination and Tube Growth in Potatoes

We have optimized the in vitro conditions for germination and tube growth of potato pollen, primarily that of tetraploid cv. Borka, in suspension culture under constant aeration and pollen density. Optimal concentration of H3BO3 and sucrose were 0.8 mM to 3.2 mM and 15%, respectively. Lactose and polyethyleneglycol (PEG 1000) were superior to sucrose in promoting pollen germination and tube growth, while substitution of sucrose with raffinose, maltose, glucose, galactose, fructose, or mannitol did not improve medium for germination. The best results were achieved with 20% PEG 1000 and 2% sucrose at 1.6 mM H3BO3. The superiority of the PEG medium was confirmed in three dihaploid genotypes. Calcium nitrate at 0.1 and 1 mM inhibited pollen germination and tube growth, and the inhibitory effect on germination was much stronger with sucrose than with PEG. No differences were found in germination rates and tube growth at pollen densities 0.5 and 1.5 mg mL-1 but increasing the density to 3 mg mL-1 reduced germin...

Cytological studies on adventitious shoots and minitubers of a monoploid potato clone

A three step procedure for adventitious shoot regeneration on leaf explants of monoploid potato clone H7322 and a minituber induction procedure on stem segments have been described. Chromosome counts on 92 adventitious shoots showed that 85% of them had been polyploidized, i.e., 71% were diploid, 1% tetraploid, and 13% were mixoploid. Cytophotometric studies on nuclei of soil grown tubers of tetraploid cv Astarte, of 1x, 2x and 4x adventitious shoots of H7322, and of diploid H2578 showed in all cases polyploidization with prominent classes up to 8C and 16C. However, nuclei of pith cells of 5 weeks old minitubers which had developed on monoploid H7322 itself or on 1x adventitious shoots of H7322 showed predominantly 1C and 2C values. Pith cells of minitubers of monoploid H7322 were screened, after iodine staining, for the presence of variant cells containing reddish-brown staining (amylose-free) starch. In more than 75% of the investigated minitubers one or a few of such variant cells were found indicating that such a variation occurs in minitubers of monoploid potato and that this variant character is expressed in cells of vegetative storage organs like potato tubers.

Effect of cultivar and seed rate of perennial ryegrass and strategic fertilizer nitrogen on the productivity of grass/white clover swards

AbstractFour cultivars of perennial ryegrass (intermediate diploid cv. Talbot and tetraploid cv. Barlatra, and late diploid cv. Parcour and tetraploid cv. Petra) were each sown at 10,20 and 30 kg ha‐1, all with 3 kg ha‐1 of white clover cv. Donna. Herbage productivity was measured over 3 harvest years, 1982–84. under two annual rates of fertilizer N (0 and 150 kg ha‐1); the 150 kg ha‐1 rate was split equally between March and August applications.Fertilizer N increased total herbage DM production; the 3‐year means for the 0 and 150 kg ha‐1 N rates were 8·04 and 8·91 t ha‐1, respectively. In successive years, total herbage responses to N (kg DM (kg N applied)‐1) were 6·6, 35 and 72 (overall mean, 58). Mean white clover DM production over the 3 years was reduced from 4·48 t ha‐1 at nil N to 2·82 t ha‐1 at the 150 kg ha‐1 rate, a fall of 37%. Grass seed rate did not influence total herbage production or white clover performance. The two intermediate perennial ryegrass cultivars had a marginal advantage in total herbage production over the two late cultivars, but white clover content and production were higher with tetraploids than diploids.It is concluded that the value of increased herbage production from strategic use of fertilizer N has to be weighed against its depressive effect on white clover performance; application of 75 kg ha ha‐1 N in both spring and autumn was excessively high if maintenance of a good white clover content in the sward is an objective. There is considerable flexibility in the grass: clover seed ratio in seeds mixtures. Modern highly‐productive perennial ryegrass varieties do not differ substantially in compatibility with white clover but tetraploids permit better clover performance than diploids.

The effect of time of harvest on seed production of three red clover cultivars

AbstractSmall plots of red clover cv. Sabtoron, S123 (diploids) and Hungaropoly (tetraploid) were harvested for seed production at two‐week intervals from 19 August to 17 October inclusive in 1981, inflorescence appearance rate, bee density and components of yield having been monitored throughout the summer. Inflorescence appearance rate reached a maximum at the end of July/early August for Hungaropoly and Sabtoron and during mid‐August for S123. Bee density followed a similar pattern. Florets and seeds per inflorescence and 1000‐seed weight decreased as flowering progressed except during the first three weeks in July. Potential seed yield was calculated from the components of yield for the harvests taken on 3 and 18 September. Losses in seed yield (difference between actual and potential) up to and during harvesting, threshing and cleaning were lower in the tetraploid cultivar (27–39%) than the diploid cultivars (35–l55%). Each cultivar had an optimum harvest time before which yield was affected by immature seeds and beyond which it was adversely affected by shedding of inflorescences and seeds and sprouting of seeds on the inflorescences. The optimum time to harvest Sabtoron was early September, Hungaropoly early to mid‐September and the late flowering cultivar S123 mid‐September when less than 4% of the inflorescences were still unripe. Seed yield and inflorescences per unit area were lower in the tetraploid cv, Hungaropoly (maximum 542 kg ha−1) than diploid cv. Sabtoron and S123 (864 and 897 kg ha−1 respectively) although the tetraptoid had heavier seeds. It is concluded that the optimum time to harvest red clover for seed production is about three or four weeks after the end of the period of rapid inflorescence production and that this coincides with the time when only a small proportion of unripe inflorescences remain.

Response of perennial and Italian ryegrass cultivars to temperature and soil water potential

SummaryThe rate of leaf extension (LER) in swards of perennial and Italian ryegrass was examined in relation to daily mean air temperature. Cultivars studied were an Italian, an Italian-perennial hybrid, a tetraploid perennial and diploid perennial cultivars in three maturity groups. A range of response to temperature was apparent. The Italian, the hybrid and the tetraploid perennial cultivar showed higher LER values than those of the diploid perennials. Amongst perennial cultivars the tetraploid cv. Reveille was shown to have a lower rate of photorespiration than the diploid cv. Gremie. These data are discussed in relation to the use of daily temperature observations in predicting leaf growth.

Potential of Serradella as a winter annual forage legume on sandy coastal soil

Abstract Three species of Serradella, Ornithopus sativus. O. pinnatus, and O. compressus cv. ‘Pitman’, each at diploid and tetraploid levels, were compared with two varieties of subterranean clover, ‘Mt. Barker’ and ‘Tallarook’, on Himatangi sandy soil. Productivity ciata are presented for mown plots for the second year of a trial in which the legumes were permitted to reseed naturally. Reseeding of the diploid serradellas and the subterranean clovers was excellent. Tetraploid O. compressus cv. ‘Pitman’ reseeded sufficiently to produce a sward in the second year, but tetraploid O. sativus and O. pinnatus failed to re-establish naturally and were resown by hand. O. sativus at both ploidy levels outyielded all other lines by about 2000 kg DM/ha (25%). Diploid O. compressus cv. ‘Pitman’ and ‘Tallarook’ subterranean clover each produced about 8000–9000 kg DM/ha. Tetraploid cv. ‘Pitman’, both lines of O. pinnalus, and ‘Mt. Barker’ were inferior. These results indicate that further evaluations of Serradella on ...

COMPETITION FOR PHOSPHATE BETWEEN A DIPLOID AND A TETRAPLOID PERENNIAL RYEGRASS

ABSTRACTThe relative uptake of P was measured in two varieties of Lolium perenne using radioactive tracer techniques. The diploid cv. Hora and the tetraploid cv. Terhoy were sown as pure stands and as 50:50 mixtures at both high and low density. Uptake from four depths 10, 20, 30 and 40 cm was examined. The results showed that: in pure stands the diploid uptake at 10 cm exceeded that of the tetraploid although at deeper levels the uptake pattern was similar; in mixtures the uptake of the tetraploid variety increased markedly at 10 cm while that of the diploid variety decreased. The diploid compensated for its decreased uptake at 10 cm by a substantial increase in uptake at 20 cm; overall the tetraploid variety had a deeper pattern of uptake than the diploid; in general, uptake at high density was greater than that at low density; the mixture showed a greater degree of P utilization than pure stands in the upper layers of the soil; when these two varieties are grown together in 50:50 mixtures the tetraploid is relatively more efficient in taking up.