Influence of genotypes and crop growth stage at time of infection on seed transmission of Maize chlorotic mottle virus

Figures & data

Table 1. List of genotypes used in the study, their source and reaction to maize lethal necrosis (MLN) disease infection.

Genotype	Source^a	Reaction to MLN infection^b
DK777	Agrovet	Tolerant
DK8031	Agrovet	Susceptible
DH02	Agrovet	Susceptible
DUMA 43	Agrovet	Susceptible
H614	Agrovet	Susceptible
H6213	Agrovet	Susceptible
H625	Agrovet	Susceptible
KH500-33A	Agrovet	Susceptible
PHB3253	Agrovet	Susceptible
PH30G19	Agrovet	Susceptible
WE5138	CIMMYT/KALRO	Tolerant
WE5139	CIMMYT/KALRO	Tolerant
KATEH 16-01	KALRO	Tolerant
KATEH16-02	KALRO	Tolerant
WE5140	CIMMYTKALRO	Tolerant

^a Refers to the source of seed. Agrovet indicates the seeds were purchased from a retail shop.

^bReference - https://mln.cimmyt.org/mln-resistanttolerant-germplasm/.

Table 2. Comparison of mean MCMV severity scores at 63 days post inoculation for 15 genotypes with that of the genotype on top row (DH02).

	DH02	DK777	DK8031	DUMA43	H614	H6213	H625	KATEH_16-01	KATEH_16-02	KH500-33A	PH30G19	PHB3253	WE5138	WE5139
DH02
DK777	1.8*
DK8031	3.3	3.3*
DUMA43	2.8	2.8	2.8
H614	2.5	2.5	2.5	2.5
H6213	3	3.0*	3	3	3
H625	3.5	3.5*	3.5	3.5	3.5	3.5
KATEH_16-01	2	2	2	2	2	2	2
KATEH_16-02	2.2	2.2	2.2	2.2	2.2	2.2	2.2	2.2
KH500-33A	3.2	3.2*	3.2	3.2	3.2	3.2	3.2	3.2	3.2
PH30G19	3.5	3.5**	3.5	3.5	3.5	3.5	3.5	3.5*	3.5*	3.5
PHB3253	3.2	3.2	3.2	3.2	3.2	3.2	3.2	3.2	3.2	3.2	3.2
WE5138	1.7**	1.7	1.7**	1.7	1.7	1.7*	1.7***	1.7	1.7	1.7*	1.7***	1.7*
WE5139	1.5**	1.5	1.5**	1.5*	1.5	1.5*	1.5***	1.5	1.5	1.5**	1.5***	1.5***	1.5
WE5140	1.5**	1.5	1.5**	1.5*	1.5	1.5*	1.5***	1.5	1.5	1.5**	1.5***	1.5***	1.5	1.5

* p = 0.05.

** p = 0.01.

*** p = 0.001.

Table 3. Seedling grow-outs samples that tested positive for MCMV from different genotypes for seed harvested in 2017 and 2018 by DAS-ELISA.

Germplasm and season of harvest	Seedlings tested	Positive MCMV samples	Seed transmission rate (%)
2017
Duma43	995	2	0.21
KH500-33A	1000	4	0.45
WE5138	963	4	0.46
DK8031	929	4	0.48
2018
DH02	1209	1	0.08

Table 4. Number of seedlings tested in samples of seedling grow-outs from different genotypes (harvested in 2018) that had a positive MCMV detection and the seed transmission rate when tested with real time reverse transcription polymerase chain reaction.

Genotype	Seedlings tested	MCMV positive samples	Seed transmission rate (%)
DK8031	243	2	1
H6213	360	1	0.29
H625	351	2	0.64
KATEH 16-01	355	1	0.3
KATEH 16-02	348	2	0.67
PH30G19	350	3	1.04
PHB3253	280	1	0.38
WE5138	337	1	0.32
WE5140	189	1	0.57

Table 5. Coefficient’s estimates, odds ratio and standard error of MCMV severity scores obtained from plants inoculated at different crop stages during the 2017 and 2018 year from the regression model.

Variable	Variable category	Estimate	S.E	p-value	Odds ratio
Crop stage	Control				1.00
	Four-leaf	3.146	0.320	<0.0001	23.23
	Eight-leaf	1.121	0.279	<0.0001	3.07
	Fifteen-leaf	0.172	0.268	0.52	1.19
	Tasselling	−0.298	0.271	0.27	0.74
Variety	DK777				1.00
	Duma43	2.326	0.236	<0.001	10.24
	H614	0.951	0.213	<0.001	2.59
Year	2017
	2018	−1.173	0.180	<0.001	0.31

S.E. standard error.

Figure 1. Mean MCMV disease severity scores, 63 days after the first inoculation for three maize varieties inoculated at crop stages V4 (four-leaf), V8 (eight-leaf), V15 (fifteen-leaf), VT- tasselling and control that was not inoculated.

Table 6. MCMV Positive samples tested in 18 groups each of seedling grow outs using real-time RT-PCR and rate of transmission via seeds obtained from plants inoculated at four- and eight-leaf stages.

	Four-leaf			Eight-leaf
Variety	No. seedlings tested	Positive samples	Seed transmission %	Seedlings tested	Positive samples	Seed transmission %
DK777	668	0	0	636	1	0.17
DUMA 43	639	0	0	652	0	0
H614	637	0	0	579	0	0

Data availability statement

The authors confirm that the data supporting the findings of this study is available within the article.