Diallel analysis of leaf disease resistance in inbred Brazilian popcorn cultivars

Advanced breeding lines and potential new cultivars of annual Medicago species were screened for resistance to phoma leaf and stem disease (caused by Phoma medicaginis) and pepper spot (caused by Leptosphaerulina trifolii) in the field, and their performances were compared with appropriate control cultivars. Medicago murex had the best overall disease resistance of the Medicago species tested. There were large differences between varieties in the incidence of both diseases. Based on end-of-season scores, the most resistant to phoma leaf disease included M. murex cv. Zodiac and SAR 3490, M. tornata SA10012, and M. truncatula cv. Parabinga, with scores 52.8 on a 0-10 scale (0, nil disease; 10, >90% leaves affected). On the basis of area under disease progress curve (AUDPC), the most resistant to phoma leaf disease, with AUDPC values of <157, included all M. murex varieties except 87FB2.30, and M. truncatula cv. Caliph. Based on end-of-season scores, the most resistant to phoma stem disease, all with scores c4, included M. murex cv. Zodiac, SAR 3490, and 87F01.48; M. sphaerocarpos cv. Orion (SEP 29.1), SEP 29.2, and SEP 30.3; and M. tornata cv. Tornafield and SA10012. Resistance to phoma stem disease in these lines was confirmed by AUDPC values, especially for M. murex cv. Zodiac, SAR3490, and 87FO1.48, and for M. tornata SA10012, with values <154. Based on end-of-season scores, the most resistant to pepper spot leaf disease included M. polymorpha cvv. Serena and Circle Valley, with scores 52.8. On the basis of AUDPC, all M. murex varieties except SAR3490 and 87FO1.5 could be included among those most resistant to pepper spot leaf disease, with AUDPC values <275. Coumestrol levels in stems ranged from 117 to 1420 mg/kg DW, with lowest levels (5330 mg/kg) in M. murex cv. Zodiac, 87FO 1.48, and GRC 87; M. sphaerocarpos cv. Orion (SEP 29.1), SEP 29.2, and SEP 26.2.1; M. tornata cv. Tornafield; and M. truncatula Z601. There was positive correlation between the severity of phoma disease on stems and end-of-season (September-November) coumestrol concentrations.

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Melatonin increases leaf disease resistance and saponin biosynthesis in Panax notogiseng

Journal of Plant Physiology ◽

10.1016/j.jplph.2021.153466 ◽

2021 ◽

pp. 153466

Author(s):

Qian Yang ◽

Jianbin Li ◽

Wenna Ma ◽

Siqi Zhang ◽

Suying Hou ◽

...

Keyword(s):

Disease Resistance ◽

Leaf Disease ◽

Saponin Biosynthesis

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DIALLEL ANALYSIS OF RESISTANCE TO BACTERIAL STALK ROT (Pectobacterium chrysanthemi pv. zeae Burk., McFad. and Dim.) IN CORN (Zea mays L.)

Indonesian Journal of Agricultural Science ◽

10.21082/ijas.v8n2.2007.p48-52 ◽

2016 ◽

Vol 8 (2) ◽

pp. 48 ◽

Cited By ~ 2

Author(s):

Nuning A. Subekti ◽

Artemio M. Salazar

Keyword(s):

Disease Resistance ◽

Combining Ability ◽

Diallel Analysis ◽

The Philippines ◽

Effective Control ◽

Gene Effects ◽

Stalk Rot ◽

Additive Gene Effects ◽

Pectobacterium Chrysanthemi ◽

Additive Gene

One of the major disease problems affecting maize farming in the Philippines is bacterial stalk rot (BSR) caused by Pectobacterium chrysanthemi pv. zeae Burk., McFad. and Dim., which is formerly known as Erwinia chrysanthemi. The annual loss due to BSR is estimated at PhP. 20 million equivalent to Rp3.5 billion. At present, there is no effective control method against BSR and, therefore, varietal improvement through breeding resistant germplasms is needed. The present study aimed to determine the combining ability and the extent of additive and non-additive genetic effects in corn inbred lines with a range of reaction to BSR. Four resistant lines (S3YB 137-1-1-B, TUPI (S3) 5-1-B, TUPI (S3) 15-2-B, and 97-835) and two susceptible lines (CML 295 and 97-733) were used as genetic materials. Generation of test entries and evaluation of disease resistance were conducted at the experimental farm station of University of the Philippines Los Banos and Institute of Plant Breeding Los Banos, respectively, during 2002 to 2003 wet seasons. Griffing’s diallel mating system Model 1, Method 1 was followed in generating the test entries to make a total of 36 entries (six selfed parental lines and 15 each of F1 crosses and their reciprocal crosses). The entries were then evaluated for disease resistance in a yield trial following a randomized complete block design (RCBD) with two replications. Results of diallel analysis showed two lines, S3YB 137-1-1-B and TUPI (S3) 5-1-B, exhibited the best general combining ability (GCA) for resistance to BSR, while the crosses S3YB 137-1-1-B x TUPI (S3) 5-1-B and TUPI (S3) 5-1-B x 97-835 performed the best specific combining ability (SCA) for the resistance. GCA effect was greater than that of SCA. This indicated that additive gene effects were found to be more important than non-additive gene effects in the expression of resistance to BSR in the six corn lines used. Therefore, breeding programs towards recurrent selection that emphasize GCA would be more appropriate for BSR resistance improvement involving those six lines.

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DIALLEL ANALYSIS OF RESISTANCE TO BACTERIAL STALK ROT (Pectobacterium chrysanthemi pv. zeae Burk., McFad. and Dim.) IN CORN (Zea mays L.)

Indonesian Journal of Agricultural Science ◽

10.21082/ijas.v8n2.2007.48-52 ◽

2016 ◽

Vol 8 (2) ◽

pp. 48

Author(s):

Nuning A. Subekti ◽

Artemio M. Salazar

Keyword(s):

Disease Resistance ◽

Combining Ability ◽

Diallel Analysis ◽

The Philippines ◽

Effective Control ◽

Gene Effects ◽

Stalk Rot ◽

Additive Gene Effects ◽

Pectobacterium Chrysanthemi ◽

Additive Gene

One of the major disease problems affecting maize farming in the Philippines is bacterial stalk rot (BSR) caused by Pectobacterium chrysanthemi pv. zeae Burk., McFad. and Dim., which is formerly known as Erwinia chrysanthemi. The annual loss due to BSR is estimated at PhP. 20 million equivalent to Rp3.5 billion. At present, there is no effective control method against BSR and, therefore, varietal improvement through breeding resistant germplasms is needed. The present study aimed to determine the combining ability and the extent of additive and non-additive genetic effects in corn inbred lines with a range of reaction to BSR. Four resistant lines (S3YB 137-1-1-B, TUPI (S3) 5-1-B, TUPI (S3) 15-2-B, and 97-835) and two susceptible lines (CML 295 and 97-733) were used as genetic materials. Generation of test entries and evaluation of disease resistance were conducted at the experimental farm station of University of the Philippines Los Banos and Institute of Plant Breeding Los Banos, respectively, during 2002 to 2003 wet seasons. Griffing’s diallel mating system Model 1, Method 1 was followed in generating the test entries to make a total of 36 entries (six selfed parental lines and 15 each of F1 crosses and their reciprocal crosses). The entries were then evaluated for disease resistance in a yield trial following a randomized complete block design (RCBD) with two replications. Results of diallel analysis showed two lines, S3YB 137-1-1-B and TUPI (S3) 5-1-B, exhibited the best general combining ability (GCA) for resistance to BSR, while the crosses S3YB 137-1-1-B x TUPI (S3) 5-1-B and TUPI (S3) 5-1-B x 97-835 performed the best specific combining ability (SCA) for the resistance. GCA effect was greater than that of SCA. This indicated that additive gene effects were found to be more important than non-additive gene effects in the expression of resistance to BSR in the six corn lines used. Therefore, breeding programs towards recurrent selection that emphasize GCA would be more appropriate for BSR resistance improvement involving those six lines.

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