Identification of Novel Sources of Resistance to Sclerotinia Basal Stalk Rot in South African Sunflower Germplasm

Abstract

Sclerotinia basal stalk rot (BSR) is a serious fungal disease that reduces yield of global sunflower (Helianthus annuus L.) production. Because limited chemical and biological controls of BSR are available and the present-day hybrids lack sufficient resistance, identification of new sources of resistance is needed to manage the disease in the future. A total of 59 cultivated oilseed sunflower accessions from the Agricultural Research Council, Grain Crops Institute, Potchefstroom, South Africa sunflower collection were evaluated for resistance to BSR in artificially inoculated field trials. Nine accessions from the South African sunflower collection were identified with a disease incidence less than or equal to the moderately resistant sunflower oilseed hybrid. These lines can be used in breeding programs to introgress the genes for resistance to Sclerotinia BSR into other adapted lines, providing a more efficient, durable, and environmentally friendly host plant resistance.

Genomic Insights Into Sclerotinia Basal Stalk Rot Resistance Introgressed From Wild Helianthus praecox Into Cultivated Sunflower (Helianthus annuus L.)

“…The Northern Great Plains states of North Dakota, South Dakota, and Minnesota are the major sunflower production states of the United States, which together produced over 87% of the total sunflower in 2021 ( USDA, 2021 ). Sclerotinia BSR is one of the predominant diseases of sunflower in this region ( Gulya et al, 1989 ; Seiler et al, 2017a ). The climatic condition of this region is highly favorable for BSR disease development during the sunflower growing season and an outbreak of the disease can cause serious economic loss for the growers ( Gulya et al, 1989 ).…”

“…Use of host genetic resistance is the most economical and effective approach for BSR management and has been used effectively in many breeding programs. Sunflower genetic resources are routinely evaluated for novel sources of BSR resistance in the cultivated and wild gene pools ( Block et al, 2009 , 2010 , 2012 ; Talukder et al, 2014b ; Seiler et al, 2017a ).…”

Genetic analysis of basal stalk rot resistance introgressed from wild Helianthus petiolaris into cultivated sunflower (Helianthus annuus L.) using an advanced backcross population

“…No complete resistance against Sclerotinia diseases has been identified in the sunflower gene pools. Increased Sclerotinia resistance has been achieved through routine mining of novel resistance sources in the sunflower primary gene pool and incorporated into breeding programs ( Miller and Gulya, 1999 ; Talukder et al., 2014a ; Seiler et al., 2017a ; Talukder et al., 2017 ; Hulke et al., 2018 ; Koehler et al., 2019 ; Money et al., 2019 ; Smart et al., 2019 ). Efforts have been made to study the nature and magnitude of BSR resistance alleles conferring quantitative genetic variations within sunflower germplasms using recombinant inbred line (RIL) populations, and a total of 20 quantitative trait loci (QTL) associated with BSR resistance were identified from two RIL populations developed from the crosses of HA441/RHA349 and PAC2/RHA266.…”

Population and genome-wide association studies of Sclerotinia sclerotiorum isolates collected from diverse host plants throughout the United States

“…S. sclerotiorum produces resting structures referred to as sclerotia that contaminate soil and can remain viable for many years, complicating disease management practices ( Bolton et al, 2006 ). Additionally, chemical control of basal stalk rot and head rot is generally ineffective and sunflower hybrids with complete resistance or even high levels of resistance to these diseases are not available ( Qi et al, 2016 ; Seiler et al, 2017 ). Breeding for sunflower lines and hybrids with improved resistance is considered the most effective and economical avenue for controlling sunflower diseases caused by S. sclerotiorum ( Qi et al, 2016 ).…”

“…Breeding for sunflower lines and hybrids with improved resistance is considered the most effective and economical avenue for controlling sunflower diseases caused by S. sclerotiorum ( Qi et al, 2016 ). Progress is being made to identify diverse sources of resistance alleles and map genetic loci contributing to sunflower resistance against S. sclerotiorum ( Davar et al, 2010 ; Amouzadeh et al, 2013 ; Talukder et al, 2016 ; Seiler et al, 2017 ; Zubrzycki et al, 2017 ; Filippi et al, 2020 ; Talukder et al, 2021 , 2022a , b ). However, resistance breeding alone may not be a durable solution.…”