Differentiate between Sugar Beet (Beta vulgaris L.) Genotypes Resistance to Root-knot Nematode, (Meloidogyne incognita) by Molecular Markers

Abstract

The application of molecular methods as complementary or alternative methods can help identifying the plants containing the resistance gene at genotypic level. Therefore, DNA markers can be useful tools for selecting resistant genotypes and can save the evaluation time and improve the precisions. Selection takes productive and genetic lines resistant to nematodes have been known in sugar beet genotypes by Polymerase chain reaction (PCR). Sugar beet (Beta vulgaris L.) is the greatest vital crops that standing following to sugar cane as sugar crop in the world, later it produces about 20 % of sucrose production annually in the world. In Egypt, Sugar beet is cultivated in 523188 faddans with an average production of 20.7 tons per faddan. Recently, reclaimed desert irrigated lands at West Nubaryia and El-Bostan regions has shown that sugar beet can be successfully grown under sandy soil area condition and its considered as the extended area for sugar beet production in Egypt. The most serious problem against sugar beet extension in new lands is root-knot nematode, Meloidogyne incognita and Meloidogyne javanica which were reported as major nematode pests of sugar beet in Egypt. Importance of employed resistance nematode sugar beet genotypes (cultivars/hybrids) in infested areas has a great concern.The present study was carried out during the growing season 2015 -2016 at pots experiment in Sabahia Agricultural Research Station, Alexandria, Egypt, for evaluating the reaction of seventeen sugar beet genotypes against the most serious nematode, (Meloidogyne incognita). The seventeen sugar beet genotypes tested in this test were twelve sugar beet commercial varieties, three sugar beet inbred lines and two sugar beet breeding materials. Computed damage index classified the seventeen sugar beet genotypes into five categories according to the varietal assessment. (Four were resistant(R), three were moderately resistant (MR), six were tolerant (T), two were susceptible (S) and two were hyper susceptible (HYS)). The results for conventional PCR indicated that genes of Hs1pro-1and HSPRO2 shows resistance to, (Meloidogyne incognita) beside the known function of these genes as resistant against cyst nematode (Heterodera schachtii). Mi-1.2 gene consider resistance to root knot nematode (Meloidogyne incognita) was found in (Mi-3) inbred line.

A quantitative and qualitative assessment of sugar beet genotype resistance to root-knot nematode, Meloidogyne incognita

“…Furthermore, the infected genotypes showed considerable differences in symptoms regarding root DI, GI, RF, final population, and SR susceptibility rate, which were consistent with those observed by Maareg et al (2009). Despite the importance of the scales in expressing the differences in the degrees of nematode development, Rf, and DI, these scales do not take into consideration the evaluation of real damage occurring in plant growth, yield, and quality characteristics of infected sugar beet (Abd-El-Khair et al, 2013;Abo-Ollo et al, 2018). Otherwise, El-Nagdi and Youssef (2016) evaluated certain sugar beet genotypes for their resistance/susceptibility against M. incognita, rendering host vigor estimated as an average of root and leaf weight potentials (total yield potential) and quality characters.…”

“…AQSCS procedure classified the eight tested sugar beet varieties into four distinguished categories; moderately resistant, tolerant, susceptible, and hyper-susceptible, almost matched with the MHPI procedure except for the number of tolerant and susceptible varieties for each (Table 8). Since AQSCS is a short period technique (45 -60 days), it can detect susceptible ones more precisely (Abo-Ollo et al, 2018). Still, it could not be with tolerant varieties because tolerant and resistant varieties were not dependent on the initial population (Pi) but more on yield assessment.…”

“…Due to the absence of effective eco-friendly nematode management methods, developing sugar beet resistant to RKNs is highly desirable (Yu, 1995;Abo-Ollo et al, 2018;Hassan et al, 2022). Improving sugar beet resistance is essential to maintain crop production while reducing ecological side effects.…”