Dry Bean and Anthracnose Development From Seeds With Varying Symptom Severity

Abstract

Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum, is a damaging seed-transmitted disease of dry beans that causes reduced seed quality and yield. Seed-to-seedling transmission of C. lindemuthinum has been documented as high as 15% in asymptomatic seeds under greenhouse conditions. Increasing pathogen colonization in seeds has been correlated with increasing anthracnose seed symptoms via qPCR, but stem colonization has not been quantified. Previous studies also have characterized seed yield and quality losses due to planting C. lindemuthinum infected seeds, but none evaluated the effect of growing asymptomatic seeds on disease and plant development under field conditions. The real-time qPCR assay developed in this study and used to detect C. lindemuthianum in the stems of seedlings as early as 15 days after planting, the first date evaluated. Field trials measured the seed-to-seedling transmission of C. lindemuthianum across levels of anthracnose symptoms in seeds ranging from healthy to severely discolored. Results from these two field trials indicated that emergence and yield decreased and foliar symptoms, pathogen detection, and incidence of symptoms on progeny seeds increased as the severity of infection in planted seeds increased. In both years, planting asymptomatic seeds resulted in higher anthracnose severity than planting healthy seeds. Yield, seed weight and incidence of symptoms on progeny seeds were not increased in asymptomatic seeds over healthy seeds in 2014 where moderate disease pressure was observed. However, these factors were significantly different in 2015 where anthracnose severity was driven up to 75% by conducive weather conditions. This serves as a strong warning to growers that planting seed grown in a field where anthracnose was present, even if those seeds are asymptomatic, can result in yield and quality losses. Planting certified dry bean seed is always recommended.

Pengaruh Tingkat infeksi antraknosa (Colletotrichum capsici) terhadap viabilitas dan vigor benih tiga varietas cabai besar (Capsicum annuum L.)

“…Program sertifikasi benih pada pengujian kesehatan benih belum menetapkan standar mutu patologis penyakit antraknosa, padahal kesehatan benih penting karena benih dapat berperan sebagai penyebar penyakit di pengolahan, penyimpanan dan pesemaian. Penyakit yang ada di benih dan bagian jaringan vegetatif tanaman seperti batang seringkali tanpa gejala kerusakan namun berkorelasi dengan perkembangan penyakit di lapangan (Halvorson et al, 2021). Penelitian yang dilakukan oleh Akhtar et al (2017) bahwa benih cabai besar yang terinfeksi C. capsici mengalami deteriorasi yang ditandai dengan penurunan viabilitas benih.…”

Evaluation of seed treatments for the control of Colletotrichum lindemuthianum and Pseudomonas savastanoi pv. phaseolicola in organic production of bean: establishing test prerequisites

“…Real time PCR (qPCR) amplification was done with the genomic DNA isolated from the fungal colonies, specific primers previously described in the literature for the detection of C. lindemuthianum were used (Gadaga et al, 2018;Halvorson et al, 2021). The amplification was performed using a Rotor Gene Q cycler (Qiagen, Hilden, Germany) with initial condition at 95°C for 3 min, followed by 95°C for 10 s, 55°C for 10 s, 72°C for 20 s, 40 cycles, and at 72°C for 5 min.…”