Study – II : Evaluations of ITC accessions for their reaction to Foc R1 and TR4

The Fusarium wilt of bananas caused by both Foc R1 and Tropical Race 4 is becoming severe in Cavendish and in the locally grown commercial cultivars of bananas grown in different banana growing regions of India.  The incidence of the disease was ranged between 5 and 60%, and sometimes more than 90% was observed.  As the disease causes death of the plants, the banana growers incur a severe yield loss and sometimes abandoning of the field or shifting to other less remunerative crops. Under these circumstances finding out resistant sources is the better option for the effective management of this deadly disease in banana. In this direction, a total of 99 exotic banana genotypes representing different genomic groups (diploids, triploids, and tetraploids) was obtained from the International Transit Centre (ITC) in Belgium through ICAR-National Bureau of Plant Genetic Resources (NBPGR), New Delhi. 
These genotypes were then subjected to screening against both Foc R1 and TR4 under both glass house and field conditions. The details of the banana accessions received from ITC, Belgium are AA (29), AB (3), BB (2), AAA (23), AAB (15), ABB (14), AAAA (4), AAAB (6), AABB (1) and Rhodoclamys (2). The suckers extracted from the mother plants of ITC accessions were employed for both glasshouse and field screening against Fusarium wilt. 

For the evaluation under glass house condition, the Foc pathogen (R1 and TR4) were mass produced separately and applied to the plants @ 30g / pot. Totally 10 plants (replications) per accessions were maintained and the disease severity was calculated five months of post Foc inoculation based on the percentage of discoloured area in the rhizome on a 0-5 scale: where 0=corm completely clean, no vascular discolouration; 1=1-5%, 2=6-25%, 3=26-50%, 4=51-75%, and 5=over 75% of discoloured rhizome (Zuo, et al. 2018). 

 In the case of field condition, the experiment was conducted in the Foc hot spot area of Muthalapuram of Theni district, TN for Foc R1 and Falka village of Katihar district of Bihar state for the evaluation against TR4. The observation on internal wilt disease score (IWDS) was taken based on the percentage of discoloured area in the rhizome at the time of harvest or when the plants were severely infected with wilt disease. Based on these observations, the wilt index was calculated as follows: Disease Index (DI) = (average of disease score of each plant/the highest disease index value) × 1004. The disease index was calculated and the average value was presented. Based on the disease index, the germplasm lines were classified into six categories as described by Zuo et al (2018) with minor modifications. The reactions were immune (PDI: 0), highly resistant (PDI: >0-20), resistant (PDI: >21-40), moderately resistant (PDI: >41-60), susceptible (PDI: >61-80) and highly susceptible (PDI: >81-100). 

Results:  

1. Glass house evaluation ITC accessions against Foc R1:  

The evaluation of all the 99 accessions under glass house condition showed that 9 accessions were resistant, 46 accessions were resistant and 33 accessions were susceptible and 10 accessions were highly susceptible to Foc R1. The details of different categories of reaction of ITC accessions are as follows:  

a. Immune (1): Plantain No.-2-513 (AAB) 

b. Highly resistant - Nil 

c. Resistant (9): A 3617/9 (AA), THA-018 (AA), GCTCV-119 (AAA), Williams-570 (AAA), Akpakpak (AAB), FHIA-23 (AAAA), FHIA-02 (AAAB), PC 12-05 (AAAB), Grande Naine-180 (AAA) 

d. Moderately resistant (46): Pisang Lilin (AA), Calcutta 4 (AA), Selangor (AA), Pisang Berlin (AA) , Microcarpa  (AA), Tjau Lagada (AA) , Pisang Madu (AA), Pu-te-La- Bum (AA), Pahang (AA),  M.ac.11-9/02 (AA),  Long Tavoy(AA),  Type 2 (AA) , Bie Yeng (AA), Pitu (AA), Pisang Jari Buaya (AA), Pisang Cici  Alas (AA) Kluai Lep Mu Nang (AA) , Pisang Buntal (AA), Safet Velchi (AB), Singapuri (BB), Yangambi KM5 (AAA), GCTCV-215 (AAA), 2390-2 (AAA), Lacatan (AAA), Robusta (AAA), Pisang Berangan (AAA), Petite Naine (AAA), Red Dacca (AAA), Dwarf Cavendish (AAA), Biu Ketip (AAA), Highgate (AAA), Cocos (AAA), Pisang Ceylan (AAB), Pisang Nangka (AAB), Popoulou (AAB), Rajapuri India (AAB), Obubit Ntnga green mutant (AAB), Uzakan (AAB), Pisang Awak (ABB), Simili Radjah  (ABB), FHIA-17 (AAAA), SH FHIA-03 (AABB), 3436-6 (AAAA), SH 34-36-9(AAAA), PV 03-44 (AAAB), FHIA-21 (AAAB) 

e. Susceptible (33): cv.Rose (AA), Pa (Rayong) (AA), Zebrina (AA), Gu Nin Chio (AA), Pisang Tongat (AA), TMB – 2 x 9128-3 (AA), Pisang Mulik (AA), Palang (AA), Ney Poovan – 0459 (AB), Tani (BB),Gros Michel (AAA). Leite (AAA), Robusta (AAA), Guineo (AAA), Chinese Cavendish (AAA), Ambiri (AAA), Igitsiri (AAA), Foconah (AAB), Maidain Plantain (AAB), Big Ebanga (AAB), Kelong Mekintu (AAB), Pisang Keling (AAB), Burro Cemsa (AAB) ,Blue Torres Strait Island (ABB), Bluggoe (ABB), Cachac (ABB), Kluai Namwa Khom (ABB), Cardaba (ABB), Blue Java (ABB), Kayinja (ABB), SH 3640 (AAAB), FHIA-01 (AAAB), Musa ornate (Rhodo)  

f. Highly susceptible (10): Pisang Mas (AA), Kunnan (AB), Pisang Lemak Manis (AAA), Figue Pomme Geante (AAB), Pisang Rajah (AAB), Saba (ABB), Dole (ABB), Monthan (ABB), Namwa Khom (ABB), Musa laterita (Rhodo) 

2. Field evaluation of ITC accessions against Foc R1:  

a. Immune (19): cv.Rose (AA), Selangor (AA), Pisang Berlin (AA), Pa (Rayong) (AA), Tjau Lagada (AA), Zebrina (AA), Gu Nin Chio (AA), Pu-te–La- Bum (AA) ,Pahang (AA), M.ac.11-9/02 (AA), Long Tavo (AA), Pisang Cici Alas (AA), Williams (AAA) , Red Dacca (AAA), Guineo (AAA), Biu Ketip (AAA) ,Pisang Nangka (AAB), Plantain No.-2 (AAB), FHIA-21 (AAAB) 

b. Highly resistant (13): Pisang Mas (AA), Pisang Mulik (AA), A 3617/9 (AA), Singapuri (BB), GCTCV-119 (AAA), Dwarf Cavendish (AAA), Akpakpak (AAB), Obubit Ntnga green mutant (AAB), FHIA-23 (AAA), SH3436-6 (AAA), FHIA-02 (AAAB), PV 03-44 (AAAB), Musa ornata (Rhodo) 

c. Resistant (16): Microcarpa (AA), Pisang Madu (AA), Bie Yeng (AA), TMB 2 x 9128-3 (AA), Kluai Lep Mu Nang (AA), THA-018 (AA), Tani (BB), Ambiri (AAA), Foconah (AAB), Maidain Plantain (AAB), Popoulou (AAB), Rajapuri India (AAB), FHIA-17 (AAAA), SH34-36-9 (AAAA), PC 12-05 (AAAB) and FHIA-03 (AABB) 

d. Moderately Resistant (14): Pisang Lilin (AA), Calcutta 4 (AA), Type 2(AA), Pisang Jari Buaya (AA), Palang(AA), Pisang Buntal (AA), Petite Naine (AAA), Grande Naine (AAA), Chinese Cavendish (AA), Highgate (AA) , Uzakan (AAB), Pisang Keling (AAB), SH 3640 (AAAB), FHIA-01 (AAAB) 

e. Susceptible (15): Pisang Tongat (AA), Pitu (AA), Yangambi KM5 (AAA), GCTCV – 215 (AAA), Robusta- 0574 (AAA), Pisang Berangan (AAA), Pisang Lemak Manis (AAA), Leite (AAA), Robusta- 003 (AAA), Igitsiri (AAA), Big Ebanga (AAB), Kelong Mekintu (AAB), Pisang Awak (ABB), Monthan (ABB), Musa laterita (Rhodo) 

f. Highly Susceptible (22): Ney Poovan (AB), Safet Velchi (AB), Kunnan (AB), Gros Michel (AAA), 2390-2 (AAA), Lacatan (AAA), Cocos (AAA), Pisang Ceylan (AAB), Figue Pomme Geante (AAB), Pisang Rajah (AAB), Burro Cemsa (ABB), Blue Torres Strait Island (ABB), Saba (ABB), Bluggoe (ABB), Cachaco (ABB), Kluai Namwa Khom (ABB), Cardaba (ABB), Dole (ABB), Blue Java (ABB), Kayinja (ABB), Simili Radjah (ABB), Namwa Khom (ABB) 

3. Evaluation of ITC accessions for their reaction to Foc TR4 under glass house conditions 

a. Immune (1): Akpakpak - AAB 

b. Highly Resistant –Nil. 

c. Resistant-(30): Pisang Mas (AA), cv. Rose (AA), Microcarpa (AA), Tjau Lagada (AA), Zebrina (AA), Pisang Madu (AA), Pahang (AA), Pisang Jari Buaya (AA), Pisang Cici Alas (AA), Kluai Lep Mu Nang (AA), Palang (AA), Safet Velchi (AB), Yangambi KM -5 (AAA), GCTCV 215 (AAA), Pisang Berangan (AAA), Petite Naine (AAA), Pisang Lemak Manis (AAA), Leite (AAA), Guineo (AAA), Highgate (AAA), Ambiri (AAA), Pisang Nangka (AAB), Pisang Keling (AAB), Blue Torres Strait Island (ABB), Dole (ABB), FHIA -23 (AAAA), SH 34-36-9 (AAAA), PV 03-44 (AAAB), FHIA- 21 (AAAB), Musa laterita (Rhodo). 

d. Moderately Resistant (50): Pisang Lilin (AA), Calcutta 4 (AA), Selangor (AA), Pisang Berlin (AA), Pa (Rayong) (AA), Gu Nin Chio (AA), Pisang Tongat (AA), Pu -te-La-Bum (AA), M.ac (11/9-02) (AA), Type 2 (AA), Bie Yeng (AA), Pitu (AA), TMB2 x 9128-3 (AA), Pisang Mulik (AA), A3617/9 (AA), THA 018 (AA), Pisang Buntal (AA), Singapuri (BB), Tani (BB), GCTCV-119 (AAA), Williams (AAA), 2390-2 (AAA), Lacatan (AAA), Robusta -0574 (AAA), Red Dacca (AAA), Dwarf Cavendish (AAA), Chinese Cavendish (AAA), Biu Ketip (AAA), Cocos (AAA), Igitsiri (AAA), Pisang Ceylan (AAB), Popoulou (AAB), Pisang Rajah (AAB), Big Ebanga (AAB), Kelong Mekintu (AAB), Burro Cemsa (ABB), Saba (ABB), Bluggoe (ABB), Cachaco (ABB), Cardaba (ABB), Blue Java (ABB), Namwakhom (ABB), FHIA -17 (AAAA), SH 34 -36-6 (AAAA), FHIA-02 (AAAB), PC 12-05 (AAAB), SH- 3640 (AAAB), FHIA-01 (AAAB), FHIA-03 (AABB), Musa ornata (Rhodo) 

e. Susceptible (11): Long Tavoy (AA), Ney Poovan -0459 (AB), Robusta-3 (AAA), Grande Naine (AAA), Figue Pomme Geante (AAB), Foconah (AAB), Obubit Ntnga green mutant (AAB), Uzakan (AAB), Kluai Namwa Khom (526), PisangAwak (ABB), Simili Radjah (ABB). 

f. Highly Susceptible (7): Kunnan (AB), Gros Michel (AAA), Maiden Plantain (AAB), Rajapuri India (AAB), Plantain No -2 (AAB), Monthan (ABB), Kayinja (ABB). 

4. Evaluation of ITC accessions for their reaction to Foc TR4 under field conditions  

a. Immune (18): Pisang Tongat (AA), M.ac.(11/9-02) (AA), Bie Yeng (AA), Pitu (AA), Pisang Jari Buaya (AA), Safet Velchi (AB), GCTCV- 215 (AAA), Pisang Berangan (AAA), Pisang Nangka (AAB), Maiden Plantain (AAB), Big Ebanga (AAB), Kelong Mekintu (AAB), Akpakpak (AAB), Plantain No -2 (AAB), Cardaba (ABB), Namwa Khom (ABB), FHIA -23 (AAAA), FHIA- 21 (AAAB). 

b. Highly Resistant (9): Zebrina (AA), TMB2 x 9128-3 (AA), Pisang Cici Alas (AA), Pisang Mulik (AA), A3617/9 (AA), THA-018 (AA), Pisang Ceylan (AAB), Simili Radjah (ABB), SH 3436-6 (AAAA). 

c. Resistant (19): Pisang Mas (AA), cv. Rose (AA), Calcutta 4 (AA), Pisang Berlin (AA), Pa (Rayong) (AA), Tjau Lagada (AA), Pu -te-La-Bum (AA), Kluai Lep Mu Nang (AA), Pisang Buntal (AA), Leite (AAA), Guineo (AAA), Popoulou (AAB), Blue Torres Strait Island (ABB), Cachaco (ABB), FHIA-17 (AAAA), FHIA- 02 (AAAB), PV 03-44 (AAAB), Musa laterita (Rhodo), Musa ornata (Rhodo). 

d. Moderately Resistant (22): Pisang Lilin (AA), Selangor (AA), Pisang Madu (AA), Kunnan (AB), Singapuri (BB), Tani (BB), GCTCV -119 (AAA), 2390-2 (AAA), Lacatan (AAA), Red Dacca (AAA), Cocos (AAA), Igitsiri (AAA), Figue Pomme Geante (AAB), Foconah (AAB), Pisang Rajah (AAB), Burro Cemsa (ABB), Saba (ABB), Dole (ABB), Blue Java (ABB), SH 3436-9 (AAAA), FHIA -01 (AAAB),  FHIA-03 (AABB). 

e. Susceptible (24): Microcarpa (AA), Pahang (AA), Long Tavoy (AA), Type 2 (AA), Ney Poovan-0459 (AB), Yangambi KM -5 (AAA), Gros Michel (AAA), Williams (AAA), Robusta 0574 (AAA), Petite Naine (AAA), Pisang Lemak Manis (AAA), Robusta (AAA), Chinese 
Cavendish (AAA), Biu Ketip (AAA), Highgate (AAA), Ambiri (AAA), Obubit Ntnga green mutant (AAB), Uzakan (AAB), Pisang Keling (AAB), Bluggoe (ABB), Kluai Namwa Khom (ABB), Pisang Awak (ABB), Monthan (ABB), Kayinja (ABB). 

f. Highly Susceptible (7): Gu Nin Chio (AA), Palang (AA), Dwarf Cavendish (AAA), Grande Naine (AAA), Rajapuri India (AAB), PC 12-05 (AAAB), SH- 3640 (AAAB). 

5. Common ITC accessions resistant to Foc R1 both under glass house and field conditions (9). 

Plantain No.-2-513 (AAB), A 3617/9 (AA), THA-018 (AA), GCTCV-119 (AAA), Williams-570 (AAA), Akpakpak (AAB), FHIA-23 (AAAA), FHIA-02 (AAAB) and PC 12-05 (AAAB)  

6. Common ITC accessions resistant to Foc TR4 both under glass house and field conditions (19). 

Akpakpak – AAB, Pisang Mas (AA), cv. Rose (AA), Tjau Lagada (AA), Zebrina (AA), Pisang Jari Buaya (AA), Pisang Cici Alas (AA), Kluai Lep Mu Nang (AA), Safet Velchi (AB), GCTCV 215 (AAA), Pisang Berangan (AAA), Leite (AAA), Guineo (AAA), Pisang Nangka (AAB), Blue Torres Strait Island (ABB), FHIA -23 (AAAA), PV 03-44 (AAAB), FHIA- 21 (AAAB), Musa laterita (Rhodo). 

7. Common ITC accessions resistant to Foc TR4 and Foc R1 both under glass house and field 
conditions (19). 

Akpakpak (AAB) and FHIA-23 (AAAA) 

8. Conclusions:  

The evaluation of 99 ITC accessions belong to genomic groups for their reaction to Fusarium wilt disease of Foc R1 and TR4 under both glass house and field conditions indicated that 9 out of 99 accessions were resistant to Foc R1 and 19 out of 99 accessions were resistant to Foc TR4. However, only two ITC accessions (Akpakpak -AAB and FHIA-23 -AAAA) were resistant to both Foc R1 and TR4. These abovesaid ITC genotypes either can be used directly for commercial purpose or in conventional breeding programmes as one of the parents of resistance or in biotechnological approach for the creation of resistant varieties through gene editing or transgenic methods.