Prohexadione-Calcium Application during Vegetative Growth Affects Growth of Mother Plants, Runners, and Runner Plants of Maehyang Strawberry

Abstract

Strawberry (Fragaria × ananassa Duch.) is an important horticultural crop that is vegetatively propagated using runner plants. To achieve massive production of runner plants, it is important to transfer the assimilation products of the mother plant to the runner plants, and not to the runner itself. Application of prohexadione–calcium (Pro–Ca), a plant growth retardant with few side effects, to strawberry is effective in inhibiting transport of assimilates to runners. This study aimed to determine the optimum application method and concentration of Pro–Ca on the growth characteristics of mother plants, runners, and runner plants for the propagation of strawberry in nurseries. Pro–Ca was applied at the rate of 0, 50, 100, 150, or 200 mg·L−1 (35 mL per plant) to plants via foliar spray or drenching under greenhouse conditions at 30 days after transplantation. Petiole lengths of mother plants were measured 15 weeks after treatment; growth was suppressed at the higher concentrations of Pro–Ca regardless of the application method. However, the crown diameter was not significantly affected by the application method or Pro–Ca concentration. The number of runners was 7.0 to 8.2, with no significant difference across treatments. Runner length was shorter at higher concentrations of Pro–Ca, especially in the 200 mg·L−1 drench treatment. However, fresh weight (FW) and dry weights (DW) of runners in the 50 mg·L−1 Pro–Ca drench treatments were higher than controls. Foliar spray and drench treatments were more effective for runner plant production than the control; a greater number of runner plants were produced with the 100 and 150 mg·L−1 Pro–Ca foliar spray treatment and the 50 and 100 mg·L−1 drench treatment. The FW and DW of the first runner plant was not significantly different in all treatments, but DW of the second runner plant, and FW and DW of the third runner plant were greatest in the 50 mg·L−1 Pro–Ca drench treatment. These results suggested that growth and production of runner plants of Maehyang strawberry were greatest under the 50 mg·L−1 Pro–Ca drench treatment.

Effects of Prohexadione Calcium Applications on Growth and Yield Characteristics of Cucumber (Cucumis sativus L.)

“…Because of effect on gibberellin inhibition, Pro-Ca decreased plant height and length between internodes of tomatoes (Altıntaş 2011), onion (El-Ghorab et al 2019, strawberries (Kim et al 2019) and eggplant (Özbay & Ergun 2015) without decreasing the number of leaves. In the current study, the similar observations were obtained until on the 50 th day in 30 mg L -1 Pro-Ca dose and until the end of the trial in 45 and 60 mg L -1 Pro-Ca doses.…”

“…Pro-Ca has a significant advantage compared to other PGRs due to its low toxicological effect and short half life in plants and soil (Bizjak et al 2012). It was determined in different plant species that the application of lower doses of Pro-Ca in post-planting period had more positive effects on plant development, yield, and fruit quality compared to its higher doses (Altuntaş 2016;Kim et al 2019).…”

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“…Similar to the findings in this study, Akdemir (2018) study in lettuce seedlings showed that the higher doses (100 and 150 mg L -1 ) of Pro-Ca increased stem diameter and decreased plant height and stem fresh weight, while the low dose (50 mg L -1 ) Pro-Ca increased stem fresh weight. Kim et al (2019) reported that 50 mg L -1 Pro-Ca application after planting increased fresh and dry weights of strawberry plant compared to control.…”

Influence of Bioregulators on Latex Yield and Proteolytic Activity of Papain Extracted from Field-grown TNAU Papaya CO. 8 under the Natural Incidence of Papaya Ring Spot Virus

“…The reason for height reduction in the treatment involving G 2 can be attributed to the action of prohexadione calcium, a gibberellin biosynthesis inhibitor that acts as a co-substrate for catalyzing hydroxylations involved in the late stages of GA biosynthesis. This retardant has been reported to mainly target an enzyme 3b-hydroxylase, which helps in the conversion of inactive GA 20 /GA 9 into highly active GA 1 /GA 4 , leading to reduced plant height and shoot length (Kim et al, 2019). It was reported that chlormequat chloride used in G 4 is also an anti-gibberellin , limiting stem elongation and causing height reduction (Rademacher, 2000).…”