Add RobSeeCo (Rob-See-Co + Innotech): 130 corn/soy varieties from the seed-guide PDF (#18)

Co-authored-by: claude <claude@jpaul.io>
Co-committed-by: claude <claude@jpaul.io>

corpus/robseeco/robseeco-rc6781.md

@@ -0,0 +1,48 @@
+# RC6781
+
+- **Vendor:** RobSeeCo
+- **Brand:** Rob-See-Co
+- **Crop:** Corn
+- **Relative maturity:** 117 days
+- **Trait(s):** DV
+- **Source:** https://www.robseeco.com/products
+- **Rating scale:** Agronomic and disease ratings 1-9, 9=Best, 1=Worst, -=not available (higher is better). Plant Height 9=Tall/1=Short; Ear Height 9=High/1=Low. Planting Rate Guideline L=Low / ML=Medium-Low / M=Medium / MH=Medium-High / H=High. Disease/pest letter codes (soy): R=resistant, MR=moderately resistant, S=susceptible. Product Fit Geography A=All, C=Central (IA/MN/WI), E=East (IN/MI/OH/PA/MD), W=West (ND/SD/NE/KS/OK/TX & West), CW=Central+West.
+- **Service area:** RobSeeCo dealer network — Western/Central Corn Belt + Dakotas (Eastern Corn Belt via Federal Hybrids/Kiser Seed)
+
+---
+
+## Agronomic Characteristics
+
+- **Emergence:** 7
+- **Seedling Vigor:** 6
+- **Root Strength:** 6
+- **Stalk Strength:** 6
+- **Green Snap:** 6
+- **Staygreen:** 7
+- **Drydown:** 7
+- **Drought Tolerance:** 6
+- **Plant Height:** 8
+- **Ear Height:** 6
+- **Test Weight:** 6
+
+## Disease Ratings
+
+- **Gray Leaf Spot:** 6
+- **Goss's Wilt:** -
+- **Northern Corn Leaf Blight:** 5
+- **Tar Spot:** -
+- **Fungicide Response (Absence of Disease in Continuous Corn):** -
+
+## Planting & Placement
+
+- **RM to Silk:** 117
+- **RM to Blacklayer:** 116
+- **GDU to Blacklayer:** 2835
+- **Planting Rate Guideline:** ML-MH
+- **Product Fit Geography:** W
+
+## Strengths
+
+- Attractive high-yielding dual purpose hybrid
+- Very good staygreen with above-average plant health
+- Strongest performance on irrigated fields in the southwest