Enhance Growth and Flower Quality of Chrysanthemum indicum L. with Application of Plant Growth Retardants

Ornamental plants are cultivated worldwide. Chrysanthemum is classified as one of the most important cut and potted flowers in most of the countries. The consumer’s expectation is to find small–compact, and full of inflorescences plants. To meet these demands, growers are tending to use plant growth retardants. Three Chrysanthemum indicum L. varieties (‘Smola White’, ‘Arber’ and ‘Vienna White’) were assessed by using four plant growth regulators (PP–Bumper 250 EC; CC–Stabilan SL; MP–Medax Top SC; and PD–Toprex SC). Results indicate that treated plants show significant decrease in the assessed parameters, although in some cases growth could be a variety–dependent factor. It can also be concluded that retardants inhibit chrysanthemum growth. PD treatments greatly inhibited the growth of the plant, and also had a negative effect on inflorescences. In conclusion, the present work strengthens the possibility of using retardants as plant growth inhibitors in Chrysanthemum cultivation.

Effects of Plant Growth Retardants on Development of Poinsettia ”Christmas Feeling” Cultivar

The poinsettias were cultivated years ago as medicinal and ornamental plants, too; but in the recent time are in the light of world flower assortment surprising with new shapes and colors in the cold season. The ornamental values of these plants are given by bracts which can have the same size as foliage leaves or even larger. The tendency of floral industry consists in obtaining high quality ornamental plants with superior marketable price. In these regards, the role of plant growth retardants in regulating the growth of poinsettia is important to obtain healthy, compact bushes and extended decoration period. The aim of the paper is to evaluate the effects of plant growth retardants on poinsettia. Five treatments with different retardants were applied as drench or spray. In the experiment four replicates and a total of 144 poinsettias were used. Treatments with paclobutrazol (60 mg/l sprayed), daminozide (2500 mg/l sprayed) and chlormequat chloride (1000 mg/l sprayed), showed the best results in case of marketability.

Production of Dianthus Caryophyllus L. Cultivar (Nanus) as A potted Flowering Plant Using Two Growth Retardants (Alar and Paclobutrazol)

The experiment of one factor was carried out in the greenhouse of the University of Kirkuk - College of Agriculture - Agricultural Research and Experiment Station for the two agricultural seasons 2020-2021, by planting the seeds of the Carnations (Nanus) plant in special dishes for planting seeds filled with peat moss on 1-10-2020, when the reaching the required size of the root system, the seedlings were transferred on 20-1-2021 to the final and required size of the pots with a diameter of (13 cm) and were treated with two types of plant growth retardants (Alar and Paclobutrazol) at two different levels in addition to the control treatment (100-200) mg.l−1 Alar, (100-200) mg.l−1 Paclobutrazol and the spraying process was repeated 15 days after the first spray. The experiment resulted in a significant superiority of Paclobutrazol at the concentration 200 mg.l−1, as it was significantly superior by giving the lowest plant height and the highest flowers diameter compared to Alar factor and the control treatment, while Alar was significantly superior at the concentration of 100 mg.l−1 by giving the largest number of plant branches and the largest number of flowers compared to Paclobutrazol and control.

​Impact of Foliar Spray of Plant Growth Retardants with Potassium on Growth Traits, Gas Exchange Parameters and Grain Yield in Foxtail Millet (Panicum italicum L.)

Background: Foxtail millet is one of the nutri-cereal foods for the people of semi arid regions. Proper nutrient management and source-sink alteration are major keys for achieving higher productivity in millets. However, potassium is not recommended to foxtail millet and the potential yield is not exploited. And also the study of source-sink alteration in foxtail millet by using plant growth regulators is meager. Methods: An experiment was conducted to study the impact of plant growth retardants viz., chlormequat chloride (CCC) and mepiquat chloride (MC) with the nutrient potassium (K2SO4 - 1%) on growth, gas exchange parameters and grain yield of foxtail millet under rainfed condition. Plant growth retardants with potassium consortium were used as foliar spray at flower initiation stage under field condition. Standard methods were used to measure the plant height, root length, number of leaves, LAD, CGR and grain yield. The photosynthetic rate, transpiration rate and leaf temperature were measured by using the instrument PPS. Result: Foliar spray of CCC (250 ppm) with 1% K2SO4 showed supremacy to enhance crop growth rate, leaf area duration, photosynthetic rate, transpiration rate and grain yield compared to other treatments. However, lowest plant height (100.7 cm) and number of leaves were observed by CCC (250 ppm) alone. Highest photosynthetic rate (26.84) and transpiration rate (17.94) were registered by CCC + K2SO4. Lowest leaf temperature of 34.1ºC was registered by 1% K2SO4 compared to control (35.6°C). CCC with K2SO4 recorded highest LAD value of 46.1 which is on par with K2SO4 alone (45.9). CCC with K2SO4 registered highest grain yield of 2.13 t ha-1 with increased yield of 18.3% over control. However, highest benefit cost ratio of ratio of 2.75 was recorded by 1% K2SO4 alone.

Productivity and Economics of Pigeonpea Genotypes as Influenced by Planting Geometry, Growth Retardant

Background: In pigeonpea, nipping is a common process which induces sprouting of secondary and tertiary branches and increases the number of pods/plant. Nipping is tedious process and requires more number of labours. Hence, it is advised to use growth retardant for better source- sink relationship and better fruit retention in pigeonpea. Chlormequat Chloride is well known growth retardant and is quickly metabolized by plants, animals and soil microbes compared to other growth retardants. Current study was planned to know the effect of growth retardants and planting geometry on yield and economics of pigeonpea genotypes.Methods: Experiment conducted during 2014-2015, comprised of twelve treatments and laid out in split-split plot design with three replications. Treatments were comprised of two genotypes [BSMR-736 and TS-3(R)], three planting geometry (90 x 20 cm, 120 x 20 cm and 150 x 20 cm) and three nipping practices (without nipping, with nipping and growth retardant chlormequat chloride spray @3ml/l). Result: Pooled data of two years indicated that planting geometry of 120 x 20 cm was significantly higher in grain yield (2408 kg/ha) over others. Spraying of growth retardant chlormequot chloride recorded the highest yield (2368 kg/ha) over nipping at 50 DAS (2138 kg/ha) and without nipping (2091 kg/ha). Net returns and B:C ratio were obtained significantly at highest level with the planting of BSMR-736 genotype at 120 x 20 cm along with spraying of chlormequot chloride at 70 DAS. Phosphatase and dehydrogenase activities were un-affected by the spray of chloromequat chloride.