Late wilt disease (LWD) caused by the fungus Magnaporthiopsis maydis poses a major threat to maize production. Developing high-yielding and resistant hybrids is vital to cope with this destructive disease. The present study aimed at assessing general (GCA) and specific (SCA) combining abilities for agronomic traits and resistance to LWD, identifying high-yielding hybrids with high resistance to LWD, determining the parental genetic distance (GD) using SSR markers and investigating its relationship with hybrid performance and SCA effects. Ten diverse yellow maize inbred lines assembled from different origins and three high-yielding testers were crossed using line × tester mating design. The obtained 30 test-crosses plus the check hybrid TWC-368 were evaluated in two field trials. Earliness and agronomic traits were evaluated in two different locations. While resistance to LWD was tested under two nitrogen levels (low and high levels) in a disease nursery that was artificially infected by the pathogen Magnaporthiopsis maydis. Highly significant differences were detected among the evaluated lines, testers, and their corresponding hybrids for most measured traits. The non-additive gene action had more important role than the additive one in controlling the inheritance of earliness, grain yield, and resistance to LWD. The inbred lines L4 and L5 were identified as an excellent source of favorable alleles for high yielding and resistance to LWD. Four hybrids L5 × T1, L9 × T1, L4 × T2, and L5 × T2, exhibited earliness, high grain yield, and high resistance to LWD. Parental GD ranged from 0.60 to 0.97, with an average of 0.81. The dendrogram grouped the parental genotypes into three main clusters, which could help in reducing number of generated crosses that will be evaluated in field trials. SCA displayed significant association with the hybrid performance for grain yield and resistance to LWD, which suggests SCA is a good predictor for grain yield and resistance to LWD.

Harpophora maydis (Cephalosporium maydis) is considered to be the most destructive pathogens causing late wilt disease of maize in Egypt. Pathogen isolation was carried out through five Governorates (Kafr El-Sheikh, Behera, Dakahlya, Menia and Sohage). Five isolates were differed in their virulence based on their pathogencity test with five cultivars (SC.10, SC.123, TWC.310, Giza-2 and Balady). The maize (SC.10) was resistant against all the isolates. While the Balady showed higher susceptibility. Isolate No.5 isolated from Sohage was the most virulent isolate (25.75%), while isolate No.4 was the least virulent isolated from Menia (1.6%). Moreover, under artificial infection, phenol contents were higher in the susceptible cultivar compared to resistant one at 30, 60 and 90 days from planting. Sugar contents measured at 30, 60 and 90 days from planting were significantly high (33.64 mg 10g-1 fresh weight) with susceptible cultivars relative to resistant one (23.18 mg 10g-1). Linear increment of phenol contents and sugars was observed with the resistant cultivar compared to susceptible one, but sugar contents were decreased after 60 days. Phenol contents were higher in resistant cultivar, while interestingly sugar contents were higher in susceptible one. For results of light microscope, thickness of sheath bundle of infected plants in resistant cultivar was higher than susceptible one, and increased over age with noninfected plants. Additionally, thickness of sheath layer in resistant and susceptible was affected after infestation process. So, phenol contents may play an essential role in resistance process against late wilt disease and sugar contents with susceptibility process.

Late wilt disease caused by the fungal pathogen Magnaporthiopsis maydis represents a major threat to maize cultivation in the Mediterranean region. Developing resistant hybrids and high-yielding offers a cost-effective and environmentally sustainable solution to mitigate yield losses. Therefore, this study evaluated genetic variation, combining abilities, and inheritance patterns in newly developed twenty-seven maize hybrids for grain yield and resistance to late wilt disease under artificial inoculation across two growing seasons. The results indicated highly significant variations among assessed hybrids for all measured traits. Combining ability analysis identified IL-306, IL-304, and IL-303 as excellent combiners for grain yield and late wilt resistance, positioning them as superior candidates for hybrid development. Additionally, IL-302 was identified as a strong general combiner for earliness, and IL-307 and IL-309 demonstrated potential for producing short-statured hybrids critical for improving lodging tolerance and maximizing yield. Specific combining ability effects indicated promising earliness, yield, and disease-resistance hybrids, including IL-303×T2 and IL-306×T1. GGE biplots presented optimal line×tester combinations, offering strategic guidance for hybrid development. The principal component analysis demonstrated strong associations between grain yield, late wilt resistance, and key agronomic traits, such as ear length and kernel number. The observed robust positive association between grain yield, late wilt resistance, and yield attributes suggests selection potential for improving maize productivity. Moreover, the genotypic correlations revealed that earlier silking, taller plants, and higher kernel counts were strongly linked to enhanced yield potential. Genetic parameter estimates indicated a predominance of non-additive genetic effects for most traits, with moderate to high broad-sense heritability suggesting substantial genetic contributions to phenotypic variance. This research provides valuable insights to support the development of disease-resistant and high-yielding maize hybrids addressing critical food security challenges.

In this study six mineral elements; Copper sulfate (Cu SO₄), Potassium sulfate (K2 SO₄), Micron Sulfure (S), Boric acid (H3 BO3), Copper sulfate + Micron Sulfure (Cu SO₄ + S) and Potassium sulfate + Boric acid (K2 SO₄ + H3 BO3) as well as fungicide; Montoro 30% were used as foliar spraying. These elements were evaluated against Cercospora, leaf spot disease on sugar beet under field conditions during two season; 2017/18 and 2018/19. All foliar applications were significantly reduced the disease severity % compared to untreated treatment during the two seasons. Potassium and combined application of Potassium and Boron treatments recorded the high value of sugar beet leaf dry weight over the control. Sulfure application led to an increase the fresh weight of sugar beet root, while Boron application increased the total soluble solid (TSS), sucrose % and purity %. Results obtained showed significant increasing (%) in catalase (CAT), peroxidase (POX) and polyphenolosxidase (PPO) activities in the case of mineral application and Montoro 30% fungicide compare with untreated treatment. However, the present study showed that foliar application of mineral elements tested in increased yield components of sugar beet, and thus is recommended to increase root yield and quality as well as can reduce disease severity.

This research aimed to evaluate some sugar beet varieties (Beta vulgaris var. saccharifera, L.) to powdery mildew disease resistance. Eight sugar beet varieties namely 9K887 (Shantala)-KWS, Allanya-KWS, B8141 (BTS Smart 9175), Melodia, LP17B4011, FD18B4018, ST21801 (Mourad) and Zeppelin were planted under field condition during two seasons 2018/2019 and 2019/2020 at the Experimental Farm, Sakha Agriculture Research Station, Agriculture Research Center (ARC), Egypt. Growth and yield traits for foliage and roots were measured, economic traits; Total soluble solids (T.S.S. %) and sucrose content were estimated. Molecular differentiation was carried by using six primers of inter simple sequence repeat (ISSR) markers. Results of studied traits showed significant differences among studied varieties. The varieties of B8141, 9K887 (Shantala) and Allanya had good characters; low percentage of disease severity, high mean values of foliage, root traits and high sucrose content in contrast with Zepplin, St21801, Mourad and FD18B4018 varieties. Results of Inter simple sequence repeat markers detect that technique was effectively differentiative produce 39 bands. Twenty-three bands were polymorphic with an average 58.97% polymorphism percentage. Polymorphic information content (PIC) ranged from 0.545 to 0.885 with an average of 0.772. Resistant varieties; Melodia, B8141, Allanya-KWS and 9K887 Shantala-KWS were distinct by presence of polymorphic band (165bp) produced by HB-8 primer. While sensitive varieties; Zepplin, ST21801, FD18B4018and LP17B4011 distinct by the presence of two polymorphic bands; (175 and 945bp) produced by 89B primer. The highest value of similarity 0.97 was found between ST21801 and Zepplin. While the lowest value 0.66 was found between B8141 FD18B4018 varieties.