Euphytica (2016) 207:35–48 DOI 10.1007/s10681-015-1524-y New source of black rot disease resistance in Brassica oleracea and genetic analysis of resistance Partha Saha . Pritam Kalia . Munish Sharma . Dinesh Singh Received: 1 May 2015 / Accepted: 22 July 2015 / Published online: 28 July 2015 Ó Springer Science+Business Media Dordrecht 2015 Abstract Black rot is the most widespread and Himjyoti x BR-207) and (Pusa Sharad x BR-207) were devastating disease in Brassica oleracea crops. The evaluated. Segregation ratios obtained were compared objective of this work was to identify new sources of by Chi square test at 5 % probability. The F1 resistance to races 1 and 4 of Xcc in 46 B. oleracea generations were resistant and segregation ratio of accessions and to understand genetics of resistance. resistant and susceptible plants indicated 3(R):1(S) in Most of the accessions were susceptible to both the F2 and 1(R):2 (Seg):1(S) in F3 which suggested that races, except accessions BR-207, BR-1, BR-202-2 and resistance to Xcc race 1 in BR-207 is governed by a AL-15 of botrytis group to Xcc race 1. The partial single dominant gene. The information obtained in this resistant plants were observed in some accessions BR- study could be valuable for black rot resistance 202-2 (90 % plants) and AL-27 (10 % plants) of breeding and in planning a systematic breeding botrytis, DJ8012 (20 % plants) of capitata, 005426 programme to incorporate the black rot resistance (10 % plants) of italica. All the accessions were into the susceptible cultivars. susceptible to Xcc race 4 except one accession (DJ8012) in cabbage (capitata group) with mean Keywords Brassica oleracea Á Black rot Á Genetics disease score of 7.0 and 10 % plants were found partial resistant. The genetics of resistance in accession BR- 207 (botrytis group) was investigated by crossing this with susceptible accessions (Pusa Himjyoti and Pusa Introduction Sharad). For the genetics study, F1,F2,F3 and backcrosses (BC1P1 and BC1P2) generations of (Pusa Brassica oleracea L. comprising crop like cauliflower, cabbage, broccoli, Brussels sprouts and kale which are P. Saha (&) Á P. Kalia widely grown vegetables in India and in other parts of Division of Vegetable Science, Indian Agriculture the world (Go´mez-Campo 1999). These crops are Research Institute, New Delhi 11002, India affected by several diseases, of which black rot caused e-mail: [email protected] by bacterium Xanthomonas campestris pv. campestris M. Sharma (Xcc) (Pammel) Dowson has been reported to be most Guru Angad Dev Veterinary and Animal Sciences devastating disease worldwide (Camargo et al. 1995; University, Ludhiana, Punjab 141004, India Taylor et al. 2002; Chen et al. 2003; Singh et al. 2011). The bacterium spreads through vascular tissue, clogg D. Singh Division of Plant Pathology, Indian Agriculture Research vessels and develops ‘V’-shaped chlorotic lesions Institute, New Delhi 11002, India (Fig. 1) (Tonguc and Griffiths 2004). Marginal leaf 123 36 Euphytica (2016) 207:35–48 Fig. 1 Black rot disease symptom in Brassica oleracea chlorosis, necrosis and darkening of leaf veins and which is generally recommended to farmers has not vascular tissue within the stem are main characteristic provided a satisfactory and durable solution; in symptoms. The disease has a wide geographical addition, it is costly and environment pollutant (Mason distribution and is destructive to these vegetables et al. 2000). Therefore, development of resistant causing yield (50–65 %) and quality loss due to varieties and/or hybrids is the best approach (Pico cultivar susceptibility (Williams 1980; Ignatov et al. et al. 1996; Lapidot et al. 1997). The utilization of host 1999; Kashyap and Dhiman 2010; Dhar and Singh resistance has been recognized as one of the most 2014). This is a seed borne bacterial disease. Besides economic and effective strategies. Numerous studies these, the disease spreads by rain drops and the have been carried out to identify new sources of pathogen survives in the crop debris, seeds, and weeds resistance to black rot, but most of them are not race for longer periods (Tonguc and Griffiths 2004). The specific resulting in difficulties to incorporate black rot pathogen remains in the vascular system of the resistant gene in desirable genetic background. Many infected plants until favourable environment for related crops of Brassica species have also been found bacterial growth take place (Lema et al. 2012). Since to exhibit resistance to Xcc (Taylor et al. 2002; Tonguc the first recognition of Xcc races by Kamoun et al. and Griffiths 2004). Presently, the control of this (1992), several studies analyzed black rot resistance in disease is complicated, and very few sources of relation to race types (Ignatov et al. 2000; Vicente resistance are available in B. oleracea groups. Specific et al. 2000; Taylor et al. 2002). Initially, Vicente et al. resistance to races 1 and/or 4 has been previously (2001) identified six races (1–6), and later on, Fargier reported in different Brassica species (Ribeiro and and Manceau (2007) added three additional races Dias 1997; Tonguc and Griffiths 2004; Griffiths et al. (7–9). Races 1 and 4 have been found to be the most 2009; Vicente et al. 2002; Singh et al. 2011). The R1 virulent, widespread and accounting for more than gene conferring resistance to race 1 is present in the B 90 % of black rot disease around the world (Vicente genome of Brassica carinata (BBCC), Brassica et al. 2001). juncea (AABB) and Brassica nigra (BB), while the It is very difficult to control this disease and it can R4 gene conferring resistance to race 4 is present in the only be achieved by the use of disease free seeds and A genome of Brassica rapa (AA), Brassica napus adoption of proper cultural practices, and the elimi- (AACC) and B. juncea (AABB) (Vicente et al. 2002; nation of other potential inoculum sources (infected Taylor et al. 2002). In B. oleracea (CC) with the C crop debris and cruciferous weeds). Chemical control, genome, specific resistance to races 1 and 4 has been 123 Euphytica (2016) 207:35–48 37 never reported. However, race-nonspecific resistance (cauliflower) are contradictory. The polygenic domi- has been identified in this species (Williams 1972; nance of inheritance was reported by Sharma et al. Sharma et al. 1995; Camargo et al. 1995; Taylor et al. (1972; Tewari et al. (1987); Thakur et al. (2003); Tonu 2002; Griesbach et al. 2003). In cabbage, Bain (1952) et al. (2013) whereas, single dominant gene was initially found resistance in the cv. Huguenot and in reported by Jamwal and Sharma (1986). Pandey et al. the Japanese cv. Early Fuji and made selections from (1995) reported that resistance to black rot in cauli- them. Hunter et al. (1987) reported resistance in the flower was governed by non-additive genes. In India, introduction from China PI 436606 (Heh Yeh da Ping available varieties/hybrids of B. oleracea crops in the Tou). This genotype together with Early Fuji has been market are susceptible to black rot disease. The extensively used in cabbage breeding resulting in farmers waste huge amount of money in managing cabbage lines like NY 4002 and Badger Inbred-16 this disease in standing crop. Most of the above utilized in the development of several resistant described resistant sources in B. oleracea are not cabbage cultivars. Jensen et al. (2005) found field commercially cultivated due to other undesirable resistance to black rot in hybrid cultivars T-689 F1, characters or these are not being utilized in developing Gianty F1, No. 9690 F1, N 66 F1 and SWR-02 F1. varieties or hybrids. There is urgent need to identify Griesbach et al. (2003) reported strong resistance in new resistant breeding lines of B. oleracea against Xcc cabbage inbred line AU 4518 and some degree of isolate and to develop resistant cultivars for wider resistance in cv. Green Challenger, Utopia, Shinzan adaptability with good quality attributes. The devel- No. 2, Natsutae, Rotan and Tenacity against mixture oped lines/varieties/hybrids can be grown in other of isolates containing races 1 and 4. Resistant source countries as breeding materials for the improvement of such as Pusa Snowball K-1 (late group cauliflower B. oleracea crops. Besides breeding strategy needs to variety) was reported by Gill (1993) under temperate be formulated using identified resistance sources to conditions. Sharma et al. (1995) reported B. oleracea develop black rot resistant varieties and/or hybrids. In var. botrytis line EC-162587 line as highly resistant this experiment, the new source of resistance and the while RSK-1301 and MRS-1 as moderately resistant genetics of resistance in B. oleracea, this will be of to black rot disease. immense use in the development of resistant varieties The progress has been limited in the development and/or hybrids against this bacterial pathogen. There- of resistant varieties and/or hybrids and elusive due fore, the present study was framed to identify new inefficient phenotyping of resistant plants and unac- black rot resistance source (s) and know the genetics of ceptable co-segregating attributes. Breeders are there- resistance in B. oleracea. fore still seeking resistant varieties with good quality and yield attributes, which requires new sources of resistance, known genetics of resistance and better Materials and methods strategies for gene transfer. Genetic resistance was proposed by Williams (1980) as an efficient approach Experimental site against this disease, along with the utilization of healthy plant material and disease-free seeds. The The experiments were carried out at research farm of contradictory report on genetics of resistance and Division of Vegetable Science, Indian agricultural involvement of resistant genes in different B. oleracea Research Institute, New Delhi, India located at an background has been reported, and these resulted in elevation of about 228 m above MSL, 20°400 north lack of development of durable resistant varieties or latitude and 77°130 east longitude.