Cut Tillers Research Articles

Evaluating the effect of cupric sulphate on morphogenic structure induction and plant regeneration in spring barley anther culture in vitro

Aim. Investigation was aimed to ascertain possibility to increase the efficiency of spring barley haploid production in anther culture in vitro by addition of cupric sulphate to the solution for cut tiller cold pretreatment and by increase of cupric sulphate concentrations in the media for morphogenic structure induction and plant regeneration. Methods. Cut tillers were cold pretreated for 5 days at 4ºC in water and in the solutions contained 5 µM and 10 µM of cupric sulphate. Isolated anthers were cultivated on agar solidified nutrient medium containing N6 macro-and MS micronutrients, physiologically active substances, maltose (9.0 %) and on the media with increased (10 µM) content of cupric sulphate. Results. No effect of cupric sulphate addition on cut tiller viability and morphogenesis in anther culture in vitro was found. The lowest plant regeneration frequency was obtained when cupric sulphate was added both to inductive and regenerative media. Сonclusions. Addition of cupric sulphate to the pretreatment solution as well as increase of this microelement concentration (up to 10 µM) in the nutrient media can’t be considered as the methodological approach suitable to enhance the efficiency of spring barley haploid production in anther culture in vitro.

Use of mannitol for cold pretreatment of isolated spikes and as a component of nutrient medium for spring barley anther culture in vitro

Aim. The investigation was aimed to compare the efficiency of mannitol as a component of spike cold pretreatment solution and of medium for spring barley haploid production via anther culture in vitro. Methods. Field-grown plants of two genotypes with a contrast androgenic capacity were used as donors. Cut tillers were pretreated in water at 4⁰C for 5 days, while aseptically isolated spikes were kept in 0.3 M mannitol for 10 days at the same temperature. Isolated anthers were inoculated on inductive media containing N6 macro-, MS micronutrients, organic supplements, maltose (9.0%); the media with and without 0.1M mannitol differed in solidifying agents. Results. In highly-responsive line DH00-126, there was an almost two-fold increase in mmgreen plant regeneration frequency (from 48 to 58 plants per 100 anthers) in all experimental variants in comparison to the control. In recalcitrant variety Mebere, the combination of tiller pretreatment in water with anther cultivation on inductive starch-gelling media supplemented with 0.1 M mannitol resulted in the highest green plant yield. Conclusions. Both methodical approaches were proved to be applicable to increase the efficiency of haploid production in spring barley anther culture in vitro.

Management of Rodent Pests in Wheat Sown under Different Tillage Systems

Investigation to manage rodent pests in wheat crop sown with different tillage methods was conducted. The results revealed maximum efficacy in the form of control success (%) on plain bait consumption and burrow count basis with conventional (92.30) followed by zero tillage (84.74) and maize residue tillage (74.38). In these, rodenticide treatments with double burrow baiting was followed by single paper baiting. Lesser % cut tillers (0.39-0.53) and damage 9.56-15.71 kg/ 0.4 ha were observed in these. Burrow count in maize residue and zero tillage was 2.15 and 1.60x more than conventional tillage. Thus, rodenticide treatments with double burrow baiting at vegetative stage in December (bromadialone followed by zinc phosphide at 15 days interval) along with paper baiting (bromadialone) at reproductive stage (end February to 1st week of March) can be recommended against rodents in wheat crop to get higher economic returns (Rs.452.36-556.81/ 0.4 ha).

Damage by Rodent in Rice-Green gram cropping system in Brahmaputra Valley Zone

The results indicated that live burrow count (LBC), trapping index (TI) and rodent damage (%) recorded at different crop growth stages increased with the advancement of the crop growth. Maximum LBC (44.46), trap index (7.11) and cut tillers (6.41%) was recorded at harvesting stage of the rice followed by ripening stage with a mean LBC of 41.06, trap index of 6.88 and 6.41% cut tillers. Field rodents started damage from tillering stage of the rice crop. Rodents establishment in the rice field was completed by the panicle initiation stage. Pea crop grown after rice i.e. from November to February, the highest incidence was recorded at harvesting stage with a mean LBC of 36.11, trap index of 4.81 and 4.44% damage. Green gram crop grown after rice faced less rodent infestation in rice-green gram sequence.

Efficiency of spring barley haploid production in anther culture in vitro: comparison of basic and improved technologies

Aim. Evaluation of innovative methodological approaches elaborated on model genotypes for usability to increase frequencies of morphogenic structure induction and plant regeneration in anther culture in vitro in spring barley diverse material. Methods. Spikes isolated from F1 and F2 hybrids of four crosses were pretreated using an improved method (4ºC, 28 days), and anthers were inoculated onto nutrient media containing chemically modified starches D5-M and D5a-1 instead of agar. In control cut tillers were emerged in water and pretreated at 4ºC for 5 days. Anthers were cultivated on agar solidified medium. Results. Positive effects of the improved method of cold pretreatment and cultivation of anthers on media solidified with starches were confirmed. The advantage of new gelling agent D5a-1 was proved. Particularly, its usage resulted in a three-fold increase in the frequency of green plant regeneration. Conclusions. In order to increase spring barley androgenic haploid yield, combination of prolonged cold pretreatment with anther cultivation on media solidified with chemically modified starches instead of agar in an integrated technological process is reasonable.
 Keywords: Hordeum vulgare L., anther culture in vitro, cold pretreatment, starch, agar, embryo formation, plant regeneration.

Incidence of lesser Bandicoot, Bandicota bengalensis in Rice-Rice cropping system in UBVZ of Assam

The result indicated that live burrow count (LBC), trapping index (TI) and rodent damage (%) recorded at different crop growth stages increased with the advancement of the crop growth of both sali and boro rice. Maximum LBC (42.82), trap index (6.66) and cut tillers (8.2%) was recorded at harvesting stage of the sali rice followed by ripening stage with a mean LBC of 36.61, trap index of 6.02 and 6.6% cut tillers. Field rodents started damage from tillering stage of the rice crop. Rodents establishment in the rice field was completed by the panicle initiation stage. Boro rice grown after sali rice i.e. from December to March, the highest incidence was recorded at harvesting stage with a mean LBC of 28.61, trap index of 3.8 and 3.3% damage. In rice-rice cropping sequence, the rodent incidence was comparatively less in boro rice than sali rice.

Effect of rodenticides and traps against lesser bandicoot rat,(Bandicota bengalensis) in rice field

An investigation was carried out at Regional Agricultural Research Station (RARS), Titabor and Instructional-Cum- Research Farm, Assam Agricultural University, Jorhat during 2013-14 and 2014-15 in boro and sali season respectively. The field trials were conducted to evaluate effectiveness by combining rodenticides with local bamboo traps against field rodents in rice. Combined effect of rodenticides and traps were evaluated at different growth stages of rice against Bandicota bengalensis in terms of live burrow count (LBC/ha), trapping index (TI) as well as per cent cut tillers in both boro and sali rice, respectively. Baiting with bromadiolone (0.005%) at panicle initiation stage and bamboo traps at milky stage recorded the highest reduction in rodent population (72.39% LBC/ha, 70.57% TI and 68.13% cut tillers) in boro and (72.27% LBC/ha, 77.13% TI and 70.77% cut tillers) in sali rice over control at harvesting stage. The second best treatment in respect of per cent reduction of LBC/ha, trap index and cut tillers was bamboo traps at maximum tillering stage and bromadiolone (0.005%) at panicle initiation stage in both boro and sali rice, respectively which recorded a reduction of 65.89% LBC/ha, 66.19% TI and 65.66% cut tillers in boro rice and 68.33% LBC/ha, 71.04% TI and 62.83% tiller damage in sali rice

The effect of cold and heat pretreatments on anther culture response of Avena sativa and A. sterilis

The effect of stress pretreatments on embryo induction in anther cultures of selected genotypes of Avena sativa and A. sterilis was tested. A heat pretreatment of isolated anthers at +32°C for 5 days was best for the A. sativa line WW 18019 and for A. sterilis line CAV 2648. Genotype dependency may exist since in ‘Stout’ heat pretreatment did not increase embryo production. For A. sterilis 13 green and three albino regenerants were produced, of which five plants (haploids) survived transfer to the greenhouse. For A. sativa, 30 various differentiation media/treatment combinations were used in an attempt to regenerate plants from embryos, with no success. Seven day cold treatment of cut tillers increased slightly the response level in ‘Stout’ and was routinely used in subsequent experiments. Maltose proved to be better then sucrose as a carbon source for the genotypes tested. Fourteen percent maltose promoted the highest induction in A. sterilis, but the quality of embryos was improved in the presence of 10% maltose for both species. Sub-optimal carbohydrate levels did not enhance embryo induction in oats.

The Effect of New Tiller Growth on Carbohydrates, Nitrogen and Seed Yield per Ear in Lolium perenneL.

To clarify whether new vegetative tillers that develop around anthesis in a Lolium perenneseed crop can depress seed yields, the possible competition for carbohydrates or nitrogen between the seeds and new tillers that develop after the onset of anthesis was investigated. In two greenhouse experiments the number of tillers per plant was varied by a combination of cutting, nitrogen supply, light quality and light intensity treatments. Two genotypes with different tillering rates were used. Seed yield per ear was largely independent of the number of tillers and regrowth of cut tillers after the onset of anthesis. It increased in one genotype, but only under low light and a reduced nutrient availability, and no new tillers were produced. The amount of water-soluble carbohydrates in the reproductive tillers increased in both clones under these conditions. Under more favourable conditions the increased tillering rate and regrowth of tillers after cutting did not adversely affect seed yield per ear in either clone, although carbohydrate reserves in the flowering tillers were sharply reduced. Tiller removal increased the concentration and amount of nitrogen in the remaining flowering tillers, irrespective of the amount of regrowth. It is concluded that competition for carbohydrates or nitrogen between the seeds and new vegetative tillers that develop after the onset of anthesis, is not a major cause of the low and variable seed yields in L. perenneseed crops. Processes within the ear itself are probably limiting.

The Physical Environment in Relation to High Frequency Callus and Plantlet Development in Anther Cultures of Wheat ( Triticum aestivum L.) cv. Chris

Summary Several physical treatments have been examined for their effects upon callus formation and plant regeneration in anther cultures of the spring wheat ( Triticum aestivum L. em. Thell) cultivar «Chris». Variation in intensity and duration of low-temperature treatment was found to result in significant differences in callus formation frequency. Also, the use of a semi-solid support medium significantly inhibited callus formation relative to liquid medium, when the optimum cold treatment was used. No significant differences existed among the above treatments for ultimate plantlet production frequencies. Optimal treatments, namely, 2 week treatment of cut tillers at 4 °C in darkness, followed by culture on liquid medium, resulted in callus formation from over 14% of anthers plated and plantlet formation from over 40% of these calli.

Stem-Borer Larval Infestation of Ryegrass Swards Under Rotationally Grazed and Cut Conditions

(1) Dipterous stem-boring larval populations were assessed in rotationally grazed or cut ryegrass swards (Lolium perenne L.) throughout 1980 and 1981. (2) Total larval populations were markedly higher under grazed than under cut conditions. Oscinella frit larvae, which were separated into two forms, were much more common in the grazed swards. 0. vastator, (present in large numbers only in 1981) was more evenly distributed in both regimes. (3) Vegetation characteristics studied were tillering, soluble nitrogen, water-soluble carbohydrate and silica contents. Tillering was a major factor implicated in larval infestation: the higher tiller numbers in grazed swards is associated with an increase in larval numbers. However, grazed tillers also appeared more susceptible to larval attack than cut tillers. (4) The increased larval populations in the grazed swards did not occur as a result of the increased soluble nitrogen levels from dung and urine voided by the grazing animals, nor as a result of a difference in the level of silica which was higher under grazing. Water-soluble carbohydrate levels were higher under the cut conditions and this may have led to a reduction in larval numbers.

The effects of plant density and frequency of cutting on the growth of cocksfoot (Dactylis glomerata L). I. The production of vegetative and reproductive tillers

To study the effects of density and cutting frequency on the reproductive phase of cocksfoot (Dactylis glomerata L.) the plants of a clone were established on a geometric scale at nine spacings ranging from 4 to 17 in, between plants, which provided densities from 9 plants to 0.5 plant per sq ft. The plants were cut every 2, 4, or 8 weeks or cut once at the end of the growing season. The cut tillers were classified as vegetative or reproductive (elongating and heading). The number of vegetative tillers per plant was reduced by high density in all treatments. A change in cutting frequency from every 8 to every 4 weeks had little effect on numbers but cutting every 2 weeks led to a large reduction in numbers. The reproductive tillers were affected by the treatments much more than the vegetative tillers. At most densities, more reproductive tillers were produced by the regularly cut plants than by the plants cut once at the end of the season. The increase was attributed to destruction of the apical dominance of early reproductive buds that inhibit the development of further reproductive tillers. Very frequent cutting and high density delayed the incidence of the reproductive phase for many weeks. The optimal density for the production of reproductive tillers changed with time. It was often lower than for vegetative tillers.

The Influence of Defoliation on the Distribution of Assimilates in Lolium multiflorum Lam

Autoradiographs were made of plants of Lolium multiflorum Lam. after 14COa had been fixed by selected leaves. The results showed that labelled compounds were not translocated to other tillers but were moved to the whole root system. This pattern of distribution was changed when all or some of the tillers on the plant were defoliated. Where a single undefoliated tiller remained, it initially supplied the cut tillers with 14C-containing products, thus reintegrating a system of apparently independent tillers. When all the tillers were partially defoliated, labelled compounds were no longer translocated to the root system. A further experiment suggested that root reserves were not mobilized for regrowth following defoliation. These results are discussed in terms of the integration of a grass plant in the vegetative state.