Advanced Journal of Seed Science and Technology (AJSST) ISSN: 2812-3425, Vol. 7(2), pp. 211-228, August, 2021. Advanced Scholars Journals
Full length Research paper
Response to selection for maize streak resistance, grain yield, and secondary traits in three quality protein maize populations in Zimbabwe
*Mariote D, 1Laing M, 2Tongoona P and 3Derera J
*P.O. Box. 3658, IIAM, Av. das FPLM, Maputo
1-2-3ACCI-Universty of KwaZulu Natal, Pietermaritzburg campus
*Corresponding Author’s E-Mail: firstname.lastname@example.org
Accepted 23 July, 2021
Maize Streak Virus disease (MSVD) is a major problem in quality protein maize (QPM) in Mozambique. Recurrent selection was applied to improve MSVD resistance in three QPM populations, Sussuma, ZM521Q and Pop62SRQ at CIMMYT-Harare Research Station in Zimbabwe, during 2003-2006. Maize streak virus disease incidence and severity were rated at four weeks after emergence and at flowering stage based on visual assessment of the whole plot. Two selection cycles were formed and evaluated. Selection intensity was 50%, and 25% in cycle 1 (C1) and cycle 2 (C2), respectively. The C1 and C2 were evaluated in a randomized complete block design with three replications in 2005/6 season. Results showed significant improvement in MSVD resistance from C1 to C2, with scores of 3.4-2.9 in Sussuma, 2.7-2.3 in ZM521Q and 3.47-3.0 in Pop62SRQ, respectively. Results also indicated increase in genetic variances (σ2G) for MSVD from C1 to C2, from 0.314 in C1 to 0.559 in C2 in Sussuma; from 0.519 in C1 to 0.640 in C2 in ZM521Q, and from 0.135 in C1 to 0.781 in C2 in Pop62SRQ. Broad sense heritability estimates (H2) ranged from moderate to high and increased from C1 to C2 in all populations. The H2 estimates were 0.83-0.94 in Sussuma; 0.70-0.88 in ZM521Q and 0.65-0.87 in Pop62SRQ. This was associated with an increase in yield of about 4.57% in Sussuma, 4.62% in ZM521Q and 4.37%) in Pop62SRQ. There was also an improvement in flintiness of the grain with texture scores of 2.7-1.5 in Sussuma, 2.9-1.9 in ZM521Q and 2.5-1.7 in Pop62SRQ. There were no significant changes in anthesis-silking interval, plant height and number of ears plant-1. This study showed that S1 recurrent selection was effective in improving QPM populations for MSVD resistance, increasing genetic variances and broad sense heritability estimates without compromising grain yield, texture, and other important characteristics.
Keywords: Maize Streak Virus disease, quality protein maize, recurrent selection, genetic variances, grain yield.