scholarly journals The implication of leaf anatomical structure for the selective breeding of lilacs

2021 ◽  
Vol 25 (5) ◽  
pp. 534-542
Author(s):  
L. M. Pshennikova

The cultivars of the common lilac (Syringa vulgaris) grown in the south of the Russian Far East are not always winter-hardy and are often damaged by fungal diseases due to a very humid climate. A promising trend in the selective breeding of lilacs in Russia is the creation of new breeding material based on the gene pool of the broadleaf lilac (S. oblata) and its hybrids in order to introduce valuable adaptive traits into cultivars. The present work aimed to identify the traits of leaf anatomy in species and cultivars of Syringa resistant and susceptible to Pseudocercospora lilacis, the causative agent of brown leaf spot disease. The study was carried out on the living collection of the Botanical Garden-Institute, Far Eastern Branch, Russian Academy of Sciences (Vladivostok). The leaf anatomical structure of two Syringa species showing different degrees of resistance to P. lilacis in the monsoon climate of the Far East (resistant S. oblata and weakly resistant S. vulgaris, and also their hybrid cultivars) has been analyzed. The differences between species, subspecies, and cultivars are quantitative: they differ in the number of spongy mesophyll layers, the cell height in the first layer of palisade mesophyll, the cell height in the upper and lower epidermises, and the thickness of both mesophylls. The interspecific hybrids resistant or weakly resistant to P. lilacis (brown leaf spot disease) mainly retain the leaf anatomy structure of the maternal plant. One of the traits determining the resistance of hybrid lilac cultivars is an increased number of spongy mesophyll layers in the leaf blade. The study of leaf anatomy has shown that the four-layered spongy mesophyll leaf parenchyma correlates with the resistance of lilacs from the subsection Euvulgaris to P. lilacis. In S. oblata, this trait is inherited down the maternal line. To establish lilac cultivars resistant to fungal diseases, it is advisable to cross the two species (S. oblata and S. vulgaris) or their cultivars using one of S. oblata subspecies as a maternal plant.

2018 ◽  
Vol 10 (6) ◽  
pp. 310
Author(s):  
Tales Poletto ◽  
Marlove F. B. Muniz ◽  
Vinícius S. Fantinel ◽  
Renata F. Favaretto ◽  
Igor Poletto ◽  
...  

Sirosporium diffusum is the causal agent of the brown leaf spot disease on pecan trees that seriously damages the foliage of adult plants and seedlings. This fungal species is difficult to grow satisfactorily in a culture medium. Therefore, the aim of this study was to evaluate the effects of different physical conditions on the development of S. diffusum. In the first assay, eight culture media and five light regimes were combined, while in the second, the three treatments that promoted highest sporulation were combined with three temperatures. The trials were conducted in a two-factorial arrangement in a fully randomized design with six replicates. V8, V8CaCO3, and CA media under a 24-h photoperiod produced the highest respective sporulations: 29 × 104, 35 × 104, and 41 × 104 conidia ml-1. The best temperature for sporulation was 20±1 °C for all culture media, especially V8CaCO3 and CA. The best artificial conditions for obtaining good mycelial growth and sporulation consisted of a photoperiod of 24 h, temperature of 20±1 °C and V8CaCO3 or CA culture medium.


2021 ◽  
Vol 27 (3) ◽  
pp. 107-114
Author(s):  
Huan Luo ◽  
Myung Soo Park ◽  
Jun Myoung Yu

During a disease survey on weeds and minor cultivated crops in Korea, a brown leaf spot disease was observed on Sonchus asper. Leaf lesions were round or irregular in shape, and grayish brown to brown with a purple margin. In severe infection, lesions enlarged and coalesced, resulting in blighting of the leaves. The isolates from these leaf lesions were identified as Alternaira sonchi based on morphological characteristics and phylogenetic analyses of Internal transcribed spacer region, Alternaria allergen a1, glyceraldehyde 3-phosphate dehydrogenase, RNA polymerase II, and translation elongation factor genes. This study provides a comprehensive description of the morphological characteristics and phylogenetical traits of A. sonchi causing brown leaf spot on S. asper in Korea.


2021 ◽  
Vol 910 (1) ◽  
pp. 012080
Author(s):  
Zeinab L. Hameed ◽  
Adnan A. Lahuf ◽  
Mundher T. Jasim ◽  
Hassan M. Mohsen ◽  
Bahaa J. Kadim ◽  
...  

Abstract During a survey in season 018, leaf spot symptoms were commonly observed on apricot (Prunus armeniaca) trees in the orchards of Al-Hussainiya district in Karbala Province of Iraq. The symptomatic leaves were gathered, the associated fungus was isolated and characterized relied on its morphological features and ITS-rDNA sequencing. The causative factor was found to be the fungus Alternaria alternata that caused distinguishable leaf spot symptoms on the inoculated leaves of apricot. Based on a review of previous references relatedof this disease in Iraq, this is the first report of the brown leaf spot disease caused by A. alternata in Karbala province of Iraq.


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