Yield responses of 12 okra cultivars to southern root-knot nematode (Meloidogyne incognita)

Abstract

AbstrAct:Meloidogyne incognita is one of the most widespread and damaging plant-parasitic nematodes throughout the world and substantially affects growth and yield of okra (Abelmoschus esculentus L).In the present study, effects of M. incognita on yield parameters of 12 okra cultivars with varying levels of resistance or susceptibility were assessed. M. incognita caused significant reductions in yield parameters of okra plants of all the cultivars. Maximum reduction of 34.1% in yield was observed in highly susceptible (HS) cultivar Moderately susceptible (MS) cultivars suffered 5.9 to 12.9% reductions in yields. In case of moderately resistant (MR) cultivars (Sanam, Dikshah, Arka Anamika, Ikra-1 and Ikra-2), the reductions in yields were the minimum and ranged from 2.9 to 6.5%. The reductions in other yield parameters of okra cultivars were observed in the order HS > S > MS > MR. As the MR cultivars suffered less damage by the nematode, they are recommended for cultivation in fields heavily infested with M. incognita. Meloidogyne incognita affects yields of okra cultivars Root-knot nematodes are considered among the top 5 major plant pathogens and the first among the 10 most important genera of plant parasitic nematodes in the world (Mukhtar et al. 2013a). They attack different crop plants, including vegetables, causing severe growth retardation due to formation of typical galls. Okra (Abelmoschus esculentus L. Moench) is one of the most important vegetable crops of the world, being popular in many tropical and subtropical countries. It is mostly cultivated for human consumption and also for industrial use as fiber (Hussain et al. 2012). Pakistan is among the leading okra producing countries, and several cultivars are cultivated throughout the year on thousands of hectares. Okra yields are very variable, ranging from 1.7 to 19 t•ha −1 (Tiendrébéogo et al. 2010). Per hectare, the yield of okra in Pakistan (8.8 t) is very low as compared to Cyprus (17.8 t), Jordan (17.7 t), Egypt (14.1 t) and Barbados (11.1 t) (Anonymous 2006). Pests and diseases are the most damaging factors for okra production. In Pakistan, Meloidogyne incognita is the dominant species and found throughout the okraproducing regions where it substantially affects growth and yield (Mukhtar et al. 2013b). Sikora and Fernandez (2005) reported severe attack of root-knot disease caused by Meloidogyne spp. on okra, and yield losses up to 27%. Incidence and severity of wilt diseases caused by fungi and bacteria have been reported to increase in many crops by root-knot infections (Shahbaz et al. 2015; TariqKhan et al. 2016). The yield losses caused by root-knot nematodes are due to the build-up of inoculum of this pathogen (Kayani et al. 2013) and continuous growing of similar okra varieties in the same field year after year (Hussain et al. 2011).The use of resistant cultivars and nematicides are the main strategies to abate yield losses caused by this nematode (Gomes et al. 2015; Silva et al. 2015). The application of nematicides, though very effective...

Crecimiento y calidad de plántulas de café (Coffea arabica) injertadas sobre Coffea canephora frente a nematodos en vivero

“…Se estimó el crecimiento y la calidad de plántulas (con el Índice de Calidad de Dickson) de los cultivares de café injertados sobre el café cultivar Robusta, en presencia y ausencia de Meloidogyne spp., estos nematodos son capaces de infectar diferentes especies de plantas, provocando disminución en su rendimiento. 26,27 Una de las variables evaluadas, AP En este sentido, investigadores han reportado la existencia de una interacción positiva entre la yema y el porta-injerto, de forma que el crecimiento y desarrollo del injerto se vea favorecido por el portainjerto 28,29 Obatã IAC 1669-20, otro cultivar de porte bajo, que injertado sobre Robusta, en presencia de nematodos logro la misma altura que Bourbon amárelo IAC 662 (inoculado). El comportamiento del injerto Obatã IAC 1669-20/Robusta (inoculado), posiblemente se deba a un efecto inhibitorio en la translocación de auxina desde la raíz hacia la parte aérea acompañado de un aumento en la translocación de auxinas de la parte aérea hacia la raíz, causado por la presencia de nematodos.…”

Development of Meloidogyne incognita on selected okra cultivars

“…Due to cost benefit ratio and the pollution, the use of chemicals is not effective. By using the resistant cultivars and the non-hosts, the nematode population can be reduced in the soil (Hussain et al, 2014;Hussain et al, 2016;Mukhtar et al, 2017a;Mukhtar et al, 2017b;Mukhtar et al, 2014;Mukhtar et al, 2013c). Therefore, the present studies were planned to screen okra cultivars against M. incognita.…”

Quantification of the damage caused by Meloidogyne enterolobii in okra

“…(Marin et al, 2017). These plant parasites cause damage that leads to a reduced vegetative development and, consequently, to a lower yield (Mukhtar et al, 2017).…”

“…The reduction of production parameters may be related to the injuries caused to the root during penetration, or to the nematode feeding (Mukhtar et al, 2017). The upward movement of water and nutrients is commonly impaired with nematode infection, as the roots have their permeability to water reduced.…”