Early in the year, in order to track progress and to assess germination rates, I make 3 or 4 counts of all of the seedlings that are germinating. My first count this year was made last weekend.
So far, there have been 5,033 germinations. Among these 2,751 were from Hulthemia crosses, and among those, there were 483 seedlings coming from crosses between Hulhemias and stripes. Over the next 6 weeks, I anticipate an additional 5,000 to 10,000 seedling germinations. By then, some of the new seedlings will be blooming for the first time.
Below is a portion of the Excel spreadsheet that I use to keep track of my seedlings.
I have found the spreadsheet to be particularly helpful when assessing the germination rates of new seed parents. The far left column under "F", contains the number of germinations for each particular cross. The percent germination can be seen in the right column. Early in the season among the better germinating seed parents, there is often a large difference in germination rates reflecting the difference in time that it takes for seeds from a particular cross to germinate. The seeds from some seed parents germinate very early, while other seed parents are late germinators. Generally, I'll get 25-30% overall germination by the end of the season.
Before using a new seed parent, I will usually check the germination rate for "OP", or open pollinated seeds first before spending (and perhaps wasting) any time on them making crosses. That is an important step, because many roses that produce abundant hips and seeds, have very poor germination rates. With one seed parent, code name N147-30, I decided to take a chance and use it since I liked it so much and it seemed to set hips well. Fortunately, it has turned out to have good germination rates (ranging from 27.27% to 38.69%). N147-30 resulted from a cross of 'Pearl Sanford' X 'Thrive!', and is a miniflora to floribunda sized rose having a nice bright red coloring and glossy foliage with above average cleanliness.
Further down on the sheet there are several new seedlings that were tested for germination rates. Two sister seedlings that I like very much, N161-1 and N161-2, are nice miniature Hulthemias that set loads of hips. Usually, I will only pick 10-15 hips each of a new seed parent to check germination rates, so as not to waste too much seedling bench space. With these two however, I had high hopes for them being good germinators and wanted to see the range of seedling possibilities, so I picked lots of hips and planted all of their seeds. As you can see, out of 1,454 seeds of N161-2 that were planted, there have been ZERO germinations so far! That is powerful evidence that time should not be wasted using it as a seed parent. It is possible that these are both later germinators since the seed parent of these two is also a late germinator, so I will wait and keep my fingers crossed. Later in the season, I will give an update on their final germination rates.