Altered sex expression by plant growth regulators: An overview in medicinal vegetable bitter gourd (Momordica charantia L.)

Abstract

Bitter gourd is one of the popular vegetables for its medicinal values. It is monoecious cucurbitaceous plants which have imbalance sex ratio of male-female flowers that causes lower fruit yield. Different research works on cucurbits like bitter gourd and other related crops in respect of plant growth regulators, plant nutrients, and priming practices have been conducted in different parts of the world. Literatures related to the present study have been reviewed and found that bitter gourd genotypes produced larger male-female ratio and the induction of male flower was earlier than that of female ones. Growth regulators have significant positive effect on yield and yield components. Application of gibberellic acid (GA 3 ) enhanced the length of main vine, but decreased the primary branches while ethylene producing chemicals Canadian Environmental Protection Act (CEPA) increased the number of primary branches per plant. Application of auxin like 1-naphthaleneacetic acid (NAA) at 50 and 100 ppm and CEPA at 150 ppm also proved to be effective in inducing earlier female flowers at lower node. Application of CEPA at 150 ppm and NAA at 50 ppm was found to be the best treatments for reducing sex ratio by increasing the female flowers by suppressing the male ones, and consequently induce higher yield.

Effects of Exogenous Application of Plant Growth Regulators on Growth, Yield, and In Vitro Gynogenesis in Cucumber

“…Similarly, TIBA induced higher numbers of pistillate flowers in cucumber, bottle gourd, cantaloupe, and watermelon (Rahman, 1970;Rahman et al, 1992;Rahman and Thompson, 1969). In our study, NAA application did not significantly affect the number of pistillate flowers, although the increase in pistillate flowers in response to NAA application has been reported in many cucurbits including cucumber, bitter gourd, and watermelon (Jadav et al, 2010;Mia et al, 2014;Rahman and Thompson, 1969). In contrast to Choudhury and Singh (1970) and Hidayatullah et al (2009) who observed an increase in the number of cucumber pistillate flowers/plant with 50 to 200 ppm and 450 mM MH application, respectively, we found that MH at 10 ppm had no significant effect on pistillate flower numbers in either cucumber cultivar in both seasons, whereas at 100 ppm, it lowered the number of pistillate flowers significantly in 'Chai Lai' in the Winter of 2013 (Tables 3 and 4).…”

“…The sex type of flowers is important for commercial cucumber production because it affects harvest date as well as relative yield. Femaleness and maleness may be altered by environmental factors (i.e., temperature, photoperiod, nutrition, endogenous levels of auxin, gibberellin, ethylene, and ABA) or by PGR application (Krishnamoorthy, 1981;Mia et al, 2014). In cucumber, sex differentiation occurs at around the two true-leaf stage and the modification of floral sex can be accomplished at this stage using various PGRs (El-Ghamriny et al, 1988).…”

“…Foliar application of PGRs has been shown to change the physiological and developmental processes, including plant vegetative growth, sex expression, yield, and yield components in cucurbits, e.g., bitter gourd, bottle gourd, fluted pumpkin, cantaloupe, watermelon, and cucumber. Therefore, various auxin [indole-3-acetic acid (IAA), NAA], auxin transport inhibitor (TIBA), cytokinin (KIN), gibberellin [gibberellic acid (GA 3 )], ABA, ethylene ethephon;CEPA)] and growth retardant (MH) have been applied exogenously to control the vegetative growth and to maximize yield of these cucurbits (Jadav et al, 2010;Mia et al, 2014;Papadopoulos et al, 2006;Rahman, 1970;Rahman et al, 1992;Rahman and Thompson, 1969;Sunny and Nwonuala, 2013). It was reported that exogenous application of PGRs may shift the sex expression in cucurbits toward femaleness, increasing the number of pistillate flowers, number of fruits/plant, and individual fruit weight as well as yield (Mia et al, 2014).…”

“…Therefore, various auxin [indole-3-acetic acid (IAA), NAA], auxin transport inhibitor (TIBA), cytokinin (KIN), gibberellin [gibberellic acid (GA 3 )], ABA, ethylene ethephon;CEPA)] and growth retardant (MH) have been applied exogenously to control the vegetative growth and to maximize yield of these cucurbits (Jadav et al, 2010;Mia et al, 2014;Papadopoulos et al, 2006;Rahman, 1970;Rahman et al, 1992;Rahman and Thompson, 1969;Sunny and Nwonuala, 2013). It was reported that exogenous application of PGRs may shift the sex expression in cucurbits toward femaleness, increasing the number of pistillate flowers, number of fruits/plant, and individual fruit weight as well as yield (Mia et al, 2014). In cucumber, Papadopoulos et al (2006) reported that a 2.5-ppm KIN foliar spray had beneficial effects on plant growth (taller plants, greater leaf area, and fresh weight of leaves and stems), resulting in higher marketable yield in the spring-summer crop and in larger fruit size in the fall-winter crop.…”

Effect of foliar spray of GA3 and NAA on sex expression and yield of bitter gourd

“…The fruit is a rich source of vitamin C, iron, phosphorous and carbohydrates (Behera, 2004). This vegetable is a different nature's bountiful gifts to mankind, which does not only have fabulous digestional properties, but also it is a storehouse of remedies for many common ailment such as diabetes, rheumatism and gout (Mia et al, 2014). The fruit accumulates bitterness with time due to build up of three pentacyclic triterpenes momordicin, momordicinin and momordicilin, and then loses the bitterness during ripening (Cantwell et al, 1996).…”