AppleDash

Appledash is the femslash ship between Rainbow Dash and Applejack in the My Little Pony television show.

Canon
The series starts off with them having a previously established relationship as friends. In the second episode, they are shown to both represent Elements of Harmony, Applejack being honesty and Rainbow Dash being loyalty. Because of this bond, they grow closer than before and become part of the Mane Six.

In episode 13 of season 1, Applejack and Rainbow Dash are competing to see who's the stronger pony. To fairly judge this, they participate in an Iron Pony Competition. They are judged by fellow friends Twilight Sparkle and Fluttershy, and as the competition continues on, more and more ponies show up to watch. In multiple parts of the competition, however, Rainbow Dash uses her wings to make the events easier for her, since Applejack is an Earth Pony. Applejack points this out, and jeers at Rainbow Dash, saying she wouldn't be able to beat her. Rainbow Dash says that she could beat her with or without wings, so they decide to participate in the Running of the Leaves. In this race, Rainbow Dash has her wings tied to her side to make sure she can't get ahead using them. They start off in the lead, taunting each other and pushing each other lightly to get the other off-course. The race continues on, and as they near the finish line, they begin shoving more aggressively, to the point where Applejack accidentally rips off the rope that was holding Rainbow Dash's wings, which makes her try to fly off with Applejack very close behind. They cross the finish line and begin to argue over who came in first, only to realize that they both tied for the last place and that because of their arguing, they lost sight of the true meaning of the race, to bring down the leaves from the trees. They realize how unsportsmanlike they performed, and decide together that it's more important to do things together as friends than to win. At the end of the episode, they run back through the woods together to take care of the leaves that got left behind.

In episode 21 of season 1, Applejack is delivering an apple tree named Bloomberg to Appleloosa, a town to the west where her cousin, Braeburn, lives. They travel on a train, with Bloomberg in the caboose, where Spike decides to take a nap. There is a stampede of buffalo who attack the train, frightening the passengers. Rainbow Dash goes on top of the train to stop one of the younger buffalo but is too late and the caboose of the train, holding Spike and Bloomberg, is left behind. Applejack is upset over the loss of Bloomberg, and Rainbow Dash tries to comfort her. She and Pinkie Pie later decide to go after the buffalo to rescue Spike and Bloomberg, and they learn that because of the trees in Appleloosa, they're unable to travel to their traditional stampeding grounds. Rainbow Dash is sympathetic, and she, Pinkie Pie and Spike return to the town to tell the other ponies about the situation. Rainbow Dash tries to make Little Strongheart, the young buffalo who separated the caboose, to explain the situation to Braeburn, but since neither of them speaks, it leads to Applejack and Rainbow Dash arguing instead.

In episode 23 of season 1, we learn about how Applejack got her Cutie Mark. When she went to Manehattan to live with her aunt and uncle, she missed life on the farm, and one day she saw a gigantic rainbow leading back to Ponyville, and realized that's where she belonged. Later in the episode, we find out that the cause of that rainbow was Rainbow Dash when she performed her first Sonic Rainboom.

In episode 15 of season 2, Applejack's family is making their famous cider, which Rainbow Dash is extremely excited to try. However, when it finally comes her turn to get some, Applejack is all out, and cider season is over. Rainbow Dash is upset, and voices her despair over the lack of cider for everyone. This is when the Flim Flam brothers bring in their Super Speedy Cider Squeezy 6000, which automatically makes cider. Everyone is enthralled and excited to get more cider, but Applejack's family is upset that the Flim Flam brothers are stealing their business. They make a bet, that whoever makes the most cider gets the farm, and the war begins. Applejack's family takes their time with theirs, producing barrels much slower than Flim and Flam who produce barrels almost automatically. As Applejack's family begins to slow down, Rainbow Dash and the rest of the Mane Six help out, and even though they made less cider, theirs was better and they got to keep the farm.

In the My Little Pony: Magic Princess app, there are two info boxes for future Rainbow Dash and future Applejack. Applejacks says she likely has a loving, loyal relationship, while Rainbow Dash's says she'll have a good honest life, referencing the opposites Element of Harmony.

Fanon
One of the main reasons this ship sailed was because there was a lot of chemistry between the two. They have similar interests, personalities, and traits which lead to them being very good friends and thus, popular ship candidates.

Fandom
Applejack/Rainbow Dash tag on AO3

Trivia

 * they are the only canon femslash ship in My Little Pony